Vegetative nervous system manages the activities of all organs involved in the implementation of the organism plant functions (nutrition, breathing, release, reproduction, circulation of liquids), and also carries out trophic innervation (I. P. Pavlov).

Sympathetic department According to its basic functions is a trophic. It is performed strengthening oxidative processes, nutrient consumption, respiratory strengthening, heart activity, increase oxygen intake to muscles. Those., Ensuring the adaptation of the body under stress and ensuring trophic. Role parasympathetic department Guarding: The narrowing of the pupil with strong lights, the braking of cardiac activity, emptying of the strip organs. Those., Providing assimilation of nutrients, energy supply.

The nature of the interaction between the sympathetic and parasympathetic departments nervous system
1. Each of the departments of the vegetative nervous system can have an exciting or braking organ for one or another: under the influence of sympathetic nerves Heartbeat is rapidly, but the intensity of the intestinal peristalsis is reduced. The influence of the parasympathetic department is influenced by the frequency of heart rate, but activity increases digestive glands.
2. If any organ is innervated by both vehicle vehicle departments, then their action is usually directly opposite: the sympathetic department enhances the reduction of the heart, and parasympathetic weakens; Parasympathetic increases the secretion of the pancreas, and sympathetic reduces. But there are exceptions: the secretory nerves for the salivary glands are parasympathetic, while the sympathetic nerves do not slow down the salivation, but cause the allocation of a small amount of thick viscous saliva.
3. It is advantageous to some organs predominantly either sympathetic, or parasympathetic nerves: sympathetic nerves are suitable for kidney, spleen, and bladder - mainly parasympathetic.
4. The activities of some organs are controlled only by one department of the nervous system - sympathetic: when activated the sympathetic department, the sweating is amplified, and when the parasympathetic activation does not change, the sympathetic fibers increase the reduction of smooth muscles, lifting hair, and parasympathetic does not change. Under the influence of the sympathetic department of the nervous system, the activity of some processes and functions may vary: the blood coagulation is accelerated, the metabolism increases more intensively, mental activity increases.

Question number 5.

Research of vegetative and somatic reactions caused by local electric irritation different areas The hypothalamus allowed V. Gesen (1954) to highlight in this brain two functionally differentiated zones. Irritation of one of them - rear and lateral regions of the hypothalamus - causes typical sympathetic effects , Expansion of pupils, lifting blood pressure, increasing heart rate, cessation of intestinal peristals, etc. The destruction of this zone, on the contrary, led to a long reduction in the tone of the sympathetic nervous system and a contrast change of all the above indicators. Hess called the area of \u200b\u200bthe rear hypothalamus ergotropic And it allowed that the highest centers of the sympathetic nervous system were localized here.

Other zone covering p redoff and front hypothalamus fields, Received name trophhotropic Since with her irritation, all signs of general were observed excitation parasympathetic nervous system, accompanied by reactions aimed at restoring and preserving the reserves of the body.

However, further studies have shown that the hypothalamus is an important integrative center of autonomous, somatic and endocrine functions., Which is responsible for the implementation of complex homeostatic reactions and is included in the hierarchically organized system of brain departments regulating visceral functions.

Reticular formation:

satomotory control

somatosensory control

veszerodite

neuroendocrine changes

biological rhythm

sleep, awakening, state of consciousness, percept

ability to perceive space and time, ability of planning, study and memory

cerebellum

The main functional purpose of the cerebellum consists in adding and correction of the activities of the other motor centers. In addition, the cerebellum is connected by numerous connections with the ret.Forction of the brain barrel, which causes its important role in the regulation of vegetative functions.

In terms of motor management, the cerebellum is responsible for:

· Regulation of postures and muscle tone- correcting slow targeted movements during their execution and coordination of these movements with reflexes of maintenance of poses;

· Proper execution Fast targeted movements, the team of which is entering the brain,

· Correction of slow targeted movements and their coordination with the reflexes of maintaining poses.

Big large hemisphey

Cora performs modulating indirect action to work internal organs Through the formation of conditionaloreflector connections. In this case, cortical control is carried out through the hypothalamus. The value of the cortex of large hemispheres of the brain in the regulation of functions of organs innervated by the vegetative nervous system, and the role of the latter as a conductor of pulses from the bark of large semi-guns to the peripheral organs is brightly detected in experiments with conditional reflexes to change the activities of internal organs.

In the regulation of vegetative functions, the frontal shares of the crust of large hemispheres are of great importance. Pavlova considered the neurons of the bark of large hemispheres involved in the regulation of the functions of the internal organs as the cortical representation of the interoceptive analyzer.

Lymbic system

1) Formation of emotions. With operations on the brain, it was found that the irritation of the almond-shaped core causes the appearance of fear, anger, rage in patients. Irritation of some zooms of the waist is molded leads to the emergence of unmotivated joy or sadness. And since the limbic system participates in the regulation of the functions of visceral systems, then all vegetative reactions arising from emotions (change in the work of the heart, blood pressure, sweating) is also carried out by it.

2. Formation of motivations. It participates in the emergence and organization of motivation. The almond-shaped core regulates food motivation. Some of its areas inhibit the activity of the saturation center and stimulate the center of hunger of the hypothalamus. Others act in the opposite way. At the expense of these centers of food motivation of the almond nucleus, behavior on delicious and tasteful food is formed. In it, there are departments regulating sex motivation. With their irritation, hypersexuality and pronounced gender motivation occurs.

3. Participation in memory mechanisms. In memorization mechanisms, a special role belongs to the hippocampus. First, it classifies and encodes all the information that should be laid in long-term memory. Secondly, it provides an extraction and reproduction of the necessary information at a particular point. It is assumed that the ability to learning is determined by the congenital activity of the corresponding neurons of hippocampus.

4. Regulation of vegetative functions and maintaining homeostasis. LS are called visceral brain, as it exercises a subtle regulation of the functions of blood circulation, respiration, digestion, metabolism, etc. The special significance of the LS is that it reacts to small deviations of the parameters of the homeostasis. It affects these functions through the vegetative centers of the hypothalamus and pituitary.

Question number 6.

The phenomenon of orbel-guinsky)

After conducting studies of the functional significance of sympathetic innervation for skeletal muscles Orbel L.A. It was found that in this influence there are two inextricably linked components: an adaptive and trophic, felting adaptation.

The adaptation component is aimed at adapting the organs to performing one or other functional loads. Shifts occur due to the fact that the sympathetic effects have a trophic effect on organs, which is expressed in changing the rate of flow of metabolic processes.

Studying the effect of SNS on skeletal muscle Frog A.G. Ginzinsky was found that if the muscle was tired to the full inability to decline to rotate the stimulation of sympathetic fibers, and then start stimulating it through the engine nerves reduced. It turned out that these changes are associated with the fact that under the influence of the SNA in the muscle there is a shortening of the chronoxia, the excitation transmission time is shortened, the sensitivity to acetylcholine increases, the oxygen consumption increases.

These influences of the SNA are distributed not only to muscle activity, but also refer to the work of receptors, synapses, various divisions of the central nervous system, ZVS, the flow of unconditional and conditional reflexes.

This phenomenon is called the adaptation-trophic effect of the SNS on the skeletal muscles (the phenomenon of the orbel-hypsinsky)

Similar information.

Regulation of tissue blood flow depending on the metabolic needs of tissues, local mechanisms of the tissues themselves are carried out. Nerve gemodynamic regulation mechanisms perform common functions such as redistribution of blood flow between different organs and tissues, strengthening or braking the pump function and, most importantly, quick control over the level of system arterial pressure.

In the regulation of blood circulation, autonomous (vegetative) nervous system takes part.

An important role in regulating blood circulation plays a sympathetic nervous system. The parasympathetic nervous system also participates in the regulation of blood circulation, mainly in the regulation of the heart activity.

Sympathetic nervous system.

Sympathetic vascular fibers in the composition of spinal nerves depart from the chest and upper lumbar spinal cord segments. They follow the ganggles of the sympathetic trunk, which is located on both sides of the spine. Then the sympathetic fibers go in two directions:

• as part of specific sympathetic nerves that innervate blood vessels internal organs and heart, as shown in the right part of the figure;
• as part of peripheral spinal nerves, which innervate blood vessels of the head, torso and limbs.

Sympathetic innervation of blood vessels.

In most tissues, all vessels (with the exception of capillaries, prokapillary sphincters and metaternoles) are innervated sympathetic nerve fibers (sympathetic vasoconstrictors).
Stimulation of sympathetic nerves of small arteries and arterioles leads to an increase in vascular resistance and, consequently, to a decrease in blood flow in tissues.
Stimulation of the sympathetic nerves of large blood vessels, especially veins, leads to a decrease in the volume of these vessels. This contributes to the progress of blood towards the heart and, therefore, plays an important role in the regulation of cardiac activity, which will be stated in the following chapters.

Sympathetic nerve fibers of the heart.

Sympathetic nerve fibers innervation and blood vessels, and heart. Sympathetic stimulation leads to strengthening cardiac activity by increasing the frequency and force of heart rate.

The role of parasympathetic nerve fibers.

Although the role of the parasympathetic nervous system in the regulation of many autonomous functions (for example, numerous functions of the digestive tract) is extremely large, it plays relatively small role in the regulation of blood circulation. The most significant is the regulation of heart rate With the help of parasympathetic nerve fibers going to the heart in the composition of wandering nerves.
Let's just say that the stimulation of parasympathetic nerves causes a significant reduction in heart rate and a slight decrease in abbreviation strength.
As part of the sympathetic nerves, a huge number of vasoconstrictor nerve fibers passes and quite a bit - vasodinating fibers. The vesseloring fibers innervate all the departments of the vascular system, but the density of their distribution in different fabrics Various. Sympathetic vesseloring effect is especially expressed in the kidneys, thin intestines, spleen and skin, but much less - in skeletal muscles and brain.

The vessels center of the brain controls the vasoconducting system.

It is located bilateral in reticular formation oblong brain and the bottom third of the bridge. Vasomotor center sends parasympathetic impulses by wandering nerves to the heart, as well as sympathetic pulses through spinal cord And peripheral sympathetic nerves in almost all arteries, arterioles and body veins.

Although the details of the organization of the Vasomotor Center are not yet clear, the experimental data allow you to select the following important functional zones in it.

1. Vasoconstrictor zonelocated bilateral in the upper front desk of the oblong brain. Axes of nerve cells located in this zone are tested in the spinal cord, where the pregganionic neurons of the sympathetic vasoconstrictor system are excited.

2. Vasodilative zonelocated bilateral in the lower veneer part of the oblong brain. Axons of nerve cells located in this zone are sent to the vasoconstrictor zone. They slow down the activity of the neurons of the vasoconducting zone and thus contribute to the extension of the vessels.

3. Sensory zone, Located bilateral in a beam of a single path in the posterior part of the oblong brain and the bridge. The neurons of this zone are obtained by signals running on sensitive nerve fibers from the cardiovascular system mainly in the composition of the wandering and language nerve. Signals emerging from the sensory zone control the activity of both the vasoconstrictor and vasodilating zones of the vessels center.

This is how reflex control over the circulatory system. An example is a baroreceptor reflex that controls the level of blood pressure.

Functional sympatholysis.

With functional sympatholysis, smooth muscle elements in the excitation focus are not capable of responding to a nervous signal while maintaining communication with the neuropal end. This is how the regulatory influence of the sympathetic nervous system is manifested, the overwhelming activity of stimulating nerve impulses.

ESSAY. The increase in the tone of the parasympathetic nervous system caused by either the vagus stimulation or direct influence on muscarinic receptors, significantly reduces the tendency of myocardial of normal and stitus ventricles to the development of fibrillations. This protective effect is the result of the antagonistic interaction of myocardial reactions to increasing the nervous and humoral activity affecting the threshold of ventricular fibrillations: these mechanisms function both in the wakeful and anesthetized animal. The results obtained are undoubtedly very important for clinical practice.

Introduction

The question of the influence of the parasympathetic nervous system on the excitability of the cells of the myocardium of ventricles is constantly reassessing. Currently, it is generally accepted that vagus innervation does not apply to the myocardium of ventricles. From the point of view of the clinician, it is obvious that although the cholinergic effects can affect tachycardia, nevertheless, the place of acetylcholine is located outside the ventricles. On the other hand, recently conducted studies suggest that the impact on the parasympathetic nervous system can change the electrical properties of the myocardium of ventricles. As shown by several groups of researchers, Vagus stimulation significantly affects the excitability of ventricle cells and their tendency to fibrillation. These effects can be mediated by the presence of a rich cholinergic innervation of a specialized conductive heart system, which was discovered both in the heart of the dog and in the heart of a person.

We have shown that the influence of Vagus on the likelihood of ventricular fibrillations (FZH) depends on the background level of the tone of the sympathetic nerves of the heart. This provision follows from a number of experimental observations. For example, the influence of Vagus increases in thoracotomized animals, which manifests an increased sympathetic tone, as well as during the stimulation of sympathetic nerves and injections of catecholamines. Such an action of Vagus on the leaning of ventricles to fibrillation is eliminated under the blockade | 3-re ^ charters.

Until now, it is definitely not established whether the parasympathetic nervous system is capable of changing ventricles to fibrillation, developing during acute myocardial ischemia. Kent and Epstein S.Souvt showed that Vagus stimulation significantly increases the threshold of FZ and reduces the inclination of the styled heart of the dog to fibrillation. Sogg in. Gillis et al. It was found that the presence of intact vagoxic nerves warns the development of FZ during the dressing of the left front descending artery of the heart of a narcotic chloral of the cat, but does not give any advantages when the right coronary artery is lining. Yoon et al. And James et al. could not identify any influence of the stimulation of Vagus on the FZH threshold during the occlusion of the left front descending coronary artery dogs. Sogg et al. It was even found that the stimulation of the parasympathetic nervous system is more like more than weakening, arrhythmias that occur when removing ligature from the artery accompanied by the reperfusion of the stamping myocardium.

This also includes a unresolved problem, whether the tonic activity of the parasympathetic nervous system is modulated by the electrical stability of the stomach cells of the animal, which is in an abnocalized state. Data obtained on drugs in narcotic animals when stimulating the nerves or drug administration is valuable information, but such approaches in which approaches Well, the artifacts and the results require confirmation on a non-nancotized intact organism. Until recently, the animal study in the waking state with such a goal was not carried out due to the lack of suitable biological models for assessing the leaning of myocardium to FZH. However, this difficulty was overcome when in " The quality of the reliable indicator of the tendency of the heart to FZ was used by the threshold of repeated extras excitation, which made it possible to abandon the need to cause FZ and carry out the associated resuscitation procedures.

The objectives of this study were as follows: 1) to study the effect of vagus stimulation and direct activation of muscarinic receptor methacarine receptors on the tenderness of the heart to FZ during acute myocardial ischemia and during referry, 2) determine whether the tonic activity of the parasympathetic nervous system changes the leaning ventricles to fibrillation With an abnocalized state of the animal, and 3) to evaluate whether the data obtained on animals is some attitude towards clinical tasks.

Material and methods

Narcotized Animal Studies

General procedures

Studies were performed on 54 healthy migratory dogs weighing from 9 to 25 kg. No less than 5 days before the study, under common pentobartic anesthesia, an opening of the chest on the left side in the fourth "intercostal space was performed. After the heart of the heart is exposed around the left front descending artery at the level of the left's left" atrium placed a can be placed with a catheter and intended for occlusion . The catheter was removed under the skin outside on the back of the head.

On the day of the study of dogs narcotized with the help of A-chloral "PS 100 mg / kg intravenously. Artificial respiration was maintained through an endotracheal tube connected to a Harvard pump, feeding a mixture of room air with 100% oxygen. The oxygen in the mixture was carried out in such a way that the arterial ro2 It was between 125 and 225 mm Hg. Art. pH arterial blood Supported in the range from 7.30 to 7.55. Arterial pressure In the abdominal aorte, changed with a catheter introduced through pearful artery and attached to the pressure sensor Statham P23DB. The (EG) electrogram (EG) of the right ventricle was recorded using a monopolar intra-limited lead.

Heart study

During the entire experiment, with the help of the stimulation of the right ventricle, constant heart rhythm was maintained. To maintain artificial rhythm and applying testing incentives, used bipolar catheter (Medtronic No. 5819), introduced through the right yarem Vienna And placed under fluoroscopic control in the area of \u200b\u200bthe right ventricle. The maintenance of artificial rhythm was achieved by "incentives whose amplitude by 50-100% was higher than the threshold, the interstitial interval was from 333 to 300 ms, which corresponds to the frequencies of the ventricular excitation from 180 to 200 per minute.

The threshold of ventricular fibrillation was determined using a single stimulus with a duration of 10 ms. This definition consisted in the following: the electrical diastole was investigated using a pulse of 4 mA with an interval of 10 ms, ranging from the end of an effective refractory period to the completion of a M-wave. Then the current increase in 2 mA increments and with such a magnitude of the stimulus continued the study of diastoles for 3 s. The smallest intensity of the stimulus causing FZ, was taken as the FZH threshold.

The following protocol of the experiment was used: the complete occlusion of the left front descending coronary artery was achieved by inflating the pre-implanted catheter with a cylinder and continued for 10 minutes. During occlusion, the FZ threshold was evaluated with a minute interval. 10 minutes after the start of occlusion, the pressure in the cylinder sharply decreased and the FZH threshold was again determined. There are two occlusion with experimental studies and without it, a separated interval of at least 20 minutes.

Defibrillation was usually carried out for 3 seconds using a DC pulse obtained by discharge of a condenser with an energy intensity of 50-100 W "C from the defibrillator.11 Magnifier. This resuscitation procedure does not significantly affect the stability of the FZH threshold.

Vagus stimulation

The cervical vagosympathic trunk cut from two sides to 2 cm below the location of the carotid artery bifurcation. An isolated bipolar electrodes were attached to the distal-in ends of the cut nerve. The nerve irritation was produced by rectangular pulses with a duration of 5 ms and a voltage of 3-15 V at a frequency of stimulation of 20 Hz. The amplitude of irritating impulses was chosen in such a way that with independent irritation of either the right, or the left-owned removal of Vagus, a heart stop was achieved. The threshold of fibrillation of ventricles was determined before, during and after bilateral stimulation of Vagus. Frequency heart Rhythm During the definition of the FZ threshold, it was constantly artificially supported at a level of 200 strikes per minute.

Introduction Metaholina

Intravenous administration Muscarinic agonist - acetyl-(b, b) chloride-methylholine (J. T. Baker Company) was carried out at a physiological solution at a rate of 5 μg / (kg-min) using the Harvard infusion pump. The maximum effect on the FZh threshold was accounted for 30 minutes after the start of the introduction; At this point, the entire sequence of testing with an occlusion of the coronary artery and reperfusion began. The introduction of the substance continued during the entire study.

Studies on wishing animals

Studies were carried out on 18 adult hymonious dogs weighing from 10 to 15 kg.

For the reversible cold blockade of the parasympathetic activity of the nerves of the heart, a special method was developed. For this, part of the wagosympochic barrel with a length of 3-4 cm was isolated and placed on the neck into the skin tube. Thus, on both sides of the neck, "Vagus loops", which separated insulated nerve segments from other cervical structures were created. This makes it possible to place cooling tips around vagus loops in order to produce a reversible blockade of nervous activity.

The relative contribution of the activity of vagus afferents and effectants to the effect produced by cooling was determined by comparing the results obtained during the cooler of the Vagus with the selective blockade of vagus effectants with the inspection of atropine.

Heart Study:

To study the tendency of the heart to FZ, the method of determining the threshold of repeated extras excitation (PE) as described previously was used. In short, the threshold of the tendency to FZ was estimated as follows: when maintaining a constant frequency of cardiac rhythm 220 beats per minute, scanning with a repeated stimulus to determine the PE threshold was carried out with an intensity of an intensity equal to the dual value of the threshold in the middle of the diastole, starting with 30 ms after the end of the refractory period. The testing stimulus was supplied every time everything earlier with a step of 5 ms, until they approached the end of the refractory period. If the PE did not occur, the amplitude of the stimulus increased by 2 mA and repeated the scanning process. PE threshold was considered to be equal to the minimum current value in which the PE occurred in two out of every three attempts. PE threshold was taken as a threshold of vulnerability OK FZH.

Psychological conditions

To study the influence of sympathetic - parasympathetic interactions in the state of wakefulness of dogs were placed in stressful conditions that increase adrenergic agonitals into the heart.

Stressful conditions were to fasten the dog in the Pavlov Machine, which caused the restriction of motor capabilities. Cables for continuous observation of EG, feeding stimuli from an artificial rhythm driver and testing incentives are connected to the heart catheters. Separate kick electric shock The duration of 5 ms was carried out from a defibrillator through copper plates (80 cm2) attached to the chest. Dogs were left in belts 10 minutes before applying an electric shock and another 10 minutes after the current. The procedure was repeated 3 days in a row. On the 4th day of the application of electrical strike, the effect of stressful conditions of content on the threshold period of the heart vulnerability to FZ is investigated to and during the blockade of vagus effectants atropine (0.05 mg / kg).

RESULTS

15l and the stimulation of cholinergic nerves on the leaning of the heart to FZ during ischemia 1mocard and during reperfusion

Studying the influence of Vagus stimulation on the FZH threshold to and and<> The time of the 10-minute period of occlusion of anterior left downward coronary artery followed by sudden and statution of blood flow was carried out on 24 dogs, drugs, drugs. In the absence of the stimulation of Vagus, the occlusion of the coronary artery and reperfusion led to a significant decrease in the threshold of fibrillation (Fig. 1), the decline in the threshold occurred in the first 2 minutes after occlusion and continued from 5 to 7 minutes. Then the threshold quickly returned to the value observed in control to occlusion. After restoring the conductivity of the coronary artery, the drop in the threshold occurred almost instantly - for 20-30 seconds, but continued not long - less than 1 min. The stimulation of Vagus significantly increased the threshold of the FZH to the occlusion of the coronary artery (from 17 ± 2 mA to Z3. ± 4 mA, p<0,05) и уменьшала снижение порога, связанное с ишемией миокарда (18±4 мА по сравнению с 6±1 мА без стимуляции, р<С0,05). Во время реперфузии никакого защитного действия стимуляции вагуса не обнаружено (3±1 мА по сравнению с 5±1 мА без стимуляции).

The effect of selective "stimulation of muscarinic receptors with a methawin on the vulnerability of a heart to FZ was investigated on 10 dogs. The introduction of methawin led to the results, qualitatively similar to those obtained during Vagus stimulation. So, Metakholin increased the threshold of FZH before and during coronary artery occlusion, But it was ineffective in the fall of the threshold associated with the reperfusion-IVII (Fig. 2).

Effect of Vagus activity on heart leaning

and spontaneous FZ with myocardial and reperfusion ischemia

The study of the influence of the stimulation of Vagus on the appearance of spontaneous FZ with occlusion of the left anterior downward coronary artery and the artery of the interventricular partition was carried out additionally on 16 dogs. With the help of artificial stimulation, the ventricle was maintained a constant cardiac rhythm frequency equal to 180 ice / min. In the absence of stimulation of the Vagus occlusion of the coronary artery you-nvalla in 7 out of 10 dogs (70%), while with the simultaneous stimulation of Vagus spontaneous FZ with occlusion

This question was studied at 10 awesome dogs, which both Vagus were chronically highlighted on the neck into the skin tubes. The impulsation in the wagosympathic trunk was reversibly blocked using cooling tips placed around skin vagus loops. The cold blockade of the left and right vagus loops increased the heart rate from 95 + 5 shots per minute to 115 ± 7 and 172+ + 16 shots per minute, respectively. When both vagus loops were cooled at the same time, the cardiac rhythm frequency increased to 208 + 20 shots per minute. All changes in cardiac rhythm have been statistically reliable with p< 0,01 (рис. 4).

Investigation of the influence of the selective blockade of Vagus Efse! Feeds using atropine on the PE threshold was carried out on 8 waking dogs contained in the stressful conditions created by immobilization in the Pavlov machine with the deposition of the electric height of the moderate severity. Before turning off the impact on the heart of the Vagus pulsation, the PE threshold was 15 + 1 mA. When administered atropine (0.05 mg / kg), the threshold decreased significantly and amounted to 8 ± 1 mA (decrease by 47%,<0,0001) (рис. 5).

This effect developed regardless of the changes in cardiac rhythm, since the heart rate frequency was maintained by a constant at the level of 200 strikes per minute during the entire time of electrical testing. The Vagus block shall with atropine insignificantly influenced the PE threshold in dogs contained in cells with unstore-coined conditions (22 + 2 mA and 19 + 3 mA to and under the action of the substance, respectively).

DISCUSSION

Currently, a significant amount of data is accumulated indicating the presence of a direct influence of the parasympathetic nervous system into chronotropic and isotropic properties and excitability of the myocardium of ventricles. It is much less proved, whether the magnitude of this effect is sufficient to explain some protective effect on the occurrence of the FZH activity of the cholinergic nerves in the ische-mutized heart. In addition, little is known about the meaning of the activity of parasympathetic nerves in the tendency of the heart to FZ in two different conditions, which may play an important role in the emergence of sudden death in humans, namely, with sudden occlusion of the coronary artery and restoring its passability with the reperfusion of the stamping region . Until now, the value of the tonic activity of Vagus to reduce the tendency to FZH is not defined. Another unresolved question is whether such a tonic activity of the parasympathetic nervous system can influence the tendency of ventricles to fibrillation with weak psycho-physiological stresses. This study sheds some light on these issues.

Effect of Vagus stimulation during myocardial ischemia and reperfusion

We found that intensive parasympathetic activity that occurs during electrical irritation of decentralized Vagus, or direct stimulation of muscarino receptors using methawin reduces the dog's heart leaning to FZ during acute myocardial ischemia. This is also confirmed by observations showing that an increase in cholinermetic activity significantly reduces the fall of the FZH threshold and the tendency to spontaneous FZ during the occlusion of the coronary artery. These effects are not associated with a change in cardiac rhythm, since its frequency was maintained at a constant level with the help of an artificial rhythm driver. Neither the stimulation of Vagus nor the activation of muskari-new receptors did no positive effect during reperfusion.

What causes the various influence of the parasympathetic nervous system on the threshold of the FZ during myocardial ischemia and during reperfusion? It is assumed that the tendency of the heart to FZ with occlusion "of the coronary artery and during reperfusion is due to various mechanisms. Probably the main role in increasing the tendency of the heart to FZ during acute occlusion of the coronary artery plays the reflex activation of the sympathetic nervous system in the heart. This hypothesis confirms that this hypothesis confirms that The change in adrenergic substances in the heart correlates well with the development of a reducing threshold of the FZH and the appearance of spontaneous FZ, with an occlusion of the coronary artery. If the effects of sympathetic amines on myocardium is reduced by surgical or pharmacologically-Iin methods, then a significant protective effect is achieved against Uzhemia Thus, the activity of the parasympathetic nervous system reduces the tendency of the heart to FZ during an occlusion of the coronary artery "due to the opposition to the profibrillery influence of increased adrenergles of activity. Such a positive effect of increasing cholinergic activity may be a consequence of inhibition of the release of the norepinephrine from the sympathetic nerve endings or a consequence of reducing the reaction of receptors to the effects of catecholamines.

However, an increase in the leaning of myocardials to fibrillation during reperfusion, apparently due to nonadener-geographic factors. Currently available data indicate that this phenomenon can be associated with the products of metabolism that is washed into the blood at cell ischemia and necrosis. It was shown that if the bloodstream in ischemic myocardium is reduced gradually or if perfusion is carried out by a solution devoid of oxygen, the frequency of occurrence of ventricular arrhythmias during the restoration of blood flow is significantly reduced. Observations showing that FZ occurs within a few seconds after a sudden restoration of coronary blood flow, also indicate participation in this process of metabolic products of metabolism, also indicate participation in this process. Preventing the effects of sympathetic substances on the heart using surgical or pharmacological intervention is ineffective to prevent FZ when restoring blood flow. And since the cholinergic agonists exhibit their protective effect only through an anti-adverergic effect, it can partially explain their inability to reduce the tendency of myocardium to FZ during reperfusion.

The strong effect of the activity of the parasympathetic nervous system on the heart rate frequency can significantly change the effect of Vagus stimulation on the leaning of the ventricle to arrhythmias. For example, Kerzner et al. It was shown that Vagus stimulation does not fully suppress arrhythmias arising from myocardial infarction. On the contrary, these researchers found that an increase in the activity of the parasympathetic nervous system or the administration of acetylcholine invariably causes ventricular tachycardia during a calm without arrhythmia phases of myocardial infarction in dogs. Such an arrhythmogen action is completely dependent on the cardiac rhythm frequency and can be warned with an artificial rhythm driver.

The effect of the tonic activity of the parasympathetic nervous system on the tendency of ventricles to fibrillation in animals in wakeful state

The results of this study indicate that H: That alone in the wakefulness of the dog, her heart is experiencing a significant tonic effect of the parasympathetic nervous system. The cold blockade or right or left Vagus leads to significant changes in the heart rate frequency; However, the effect is more pronounced in the blockade of the right Vagus (see Fig. 4). This corresponds to the fact that the right Vagus has the prevailing effect on the synate-pool node with some imposition of influence from the left "Aguus. Thus, the maximum increase in the cardiac rhythm rate occurs while cooling the right and left vagus nerves.

Having established that the tonic activity of the parasympathetic nervous system has a significant impact on the drink-siegeless fabric, it makes sense to explore whether it is possible to identify any influence of the activity of Vagus on the electrical properties of the ventricle. In these experiments, atropine was used for the selective blockade of the activity of vagus effectants. Dogs were placed in Pavlov Machine for immobilization in order to increase the sympathetic effect on the heart. Such a planning of the experiment allowed to study the effect of the interaction of sympathetic and parasympathetic reactions to the leaning of myocardium to FZ in waking animals. We have established that the introduction of relatively low doses of atropyne (0.05 mg / kg) leads to almost 50% decrease in the threshold of ventricular fibrillation. This makes it possible to conclude that the significant tonic activity of the Vagus in the waking animal contained under stressful conditions, charabically weakens the profibrillery effect of eversic psycho-physiological incentives.

In addition, when using such an experimental scheme, the protective effect of Vagus is most likely due to antagonistic to the adrenergic mechanism of action. This assumption is confirmed by two types of observations. First, our previous studies have shown that the tendency of myocardium to fibrillation in such a model of stressful conditions closely correlates with the level of Catecholamines circulating in the blood, and that the prevention of the sympathetic effect on the heart is either using a beta blockade, or with sympathectomy significantly reduces the increase caused by stressful conditions. Fibrillation addictions. Secondly, the observations of De Silva et al. It is shown that an increase in the tonic effects of the parasympathetic nervous system with the introduction of morphine dogs that are in stressful immobilization conditions, in -... enjugates the threshold of FZ to the value observed in the absence of stressful effects. When the activity of vagus effectants is blocked by atropine, the bulk of the morphine protective action disappears. The introduction of morphine in nonstore-gene conditions is not able to change the threshold of FZ, apparently because in these conditions adrenergic effect on the heart is weak.

These data indicate that the activation of wandering nerves regardless of whether it arises spontaneously or caused by a pharmacological agent, has a protective effect on myocardium, reducing its tendency to FZ during stress. This beneficial effect is likely due to the antagonistic influence of the increased activity of the parasympathetic nervous system on the effect of increasing adrenergic activity in the heart.

Clinical application

More than 40 years ago it was shown that the introduction of a cholinergic substance - acetyl-beta-methylholine chloride, prevents ventricular arrhythmias caused by the introduction of adrenaline. Recently, in a number of studies it was reported that the impacts similar to the activation of the parasympathetic nervous system, such as stimulation of the carotid sine or the introduction of vagotonic agents, reduce the frequency of ventricular extrasystole and prevent ventricular tachycardia. Since cardiac glycosides increase the tonic effect of a wandering nerve on the heart, we used the action of digitalis to suppress ventricular arrhythmias. However, this clinical area requires further research.

This study was conducted by the Research Laboratory of Cardiovascular Diseases of the Harvard School of Health, Boston, Massachusetts. It was also supported by the subsidies of the MN-21384 National Institute of Mental Health and the HL-07776 Subsidy of the National Heart Institute, the Lungs and Blood of National Institutes of Health, Betar, Maryland.

LIST Literature

1. Kent. M., Smith e . R., REDWOOD D. R. ET AL. Electrical Stability of Acu-

tELY ISCHEMIC MYOCARDIUM: INFLUENES OF HEART RATE AND VAGAL STIMULATION.-CIRCULATION, 1973, 47: 291-298.

2. Kent K. M., Epstein S. E., Cooper T. et al. Cholinergic Innervation Of The

canine and Human Ventricula Conducting System: Anatomic and Elec-Trophysiological Correlation.-Circulation, 1974, 50: 948-955.

3. Kolman B. S-, Verrier R. L., Lown B. The Effect of Vagus Nerve Stimula-

tion Upon Vulnerability of the Canine Ventricular. Role of Cympathetic-Parasympathetic interactions.-Circulation, 1975, 52: 578-585.

4. Weiss T. ., Lattin G. M., Engelman K. Vagally Mediated Supression Of Pre-

mature Ventricular Contractions in Man.-am. Heart J., 1977, 89: 700-707.

5. Waxman M. in ., Wald R. W. Termination of Ventricular Tacycardia by An

increase in Cardiac Vagal Drive.-Criculation, 1977, 56: 385-391.

6. Kolman B. S., Verrier R. L., Lown B. Effect of Vagus Nerve Stimulation

upon Excitability of the Canine Ventricle: Role of Sympathetic-Parasympa-thetic interactions.-am. J. Cardiol., 1976, 37: 1041-1045.

7. Loon M. S., Han J., Tse W. W. et al Effects of Vagal Stimulation, ATROPINE,

aND PROPRANOLOL ON FIBRILLATION THRESHOLD OF NORMAL AND ISCHEMIC VENTRICLES.-AM. Heart J., 1977, 93: 60-65.

8. Lown B. ., Verrier R. L. Neural Activity and Ventricular Fibrization.-New

ENGL. J. Med., 1976, 294: 1165-1170.

9. Coor P. In ., Gillis R. A. Role of the Vagus in the Cardiovascular Chenges

induced by Coronary Occlusion.- Circulation 1974, 49: 86-87.

10. Coor P. in ., Pearle D. L., Gillis R. A. Coronary Occlusion Site As A Determi

nANT OF THE CARDIAC RHYTHM EFFECTS OF ATROPINE AND VAGOTOMY.-AM. He.

aRT J., 1976, 92: 741-749.

11. James R. G. G., ARNOLD J. M. O., ALLEN 1. D. et al. The Effects of Heart

rate, Myocardial ISChemia and Vagal Stimulation on the Threshold for Ventricular Fibrization.-Circulation, 1977, 55: 311-317.

12. Corr P. B., Penkoske P. A., Sobel. E. . ADRENERGIC INFLUENES ON ARRHYRH-

mIAS DUE TO CORONARY OCCLUSION AND REPERFUSION.-BR. Heart J., 1978, 40 (Suppl.), 62-70.

13. Matta R. J., Verrier R. L., Lown B. The Repetitive ExtraSystole AS An In

dEX OF VULBERABILITY TO VENTRICULAR FIBRILLATION.-AM. J. Physiol., 1976,

230: 1469-1473.

14. Lown B. ., Verrier R. L., Corbalan R. Psychological Stress and Threshold

for Repetitive Ventricular Response.-Science, 1973, 182: 834-836.

15. Axelrod P. J., Verrier R. L., Lown B. Vulnerability to Ventricular Fibril-

lation During Acute Coronary Arterial Occlusion and Release.-Am. J. Car-Diol, 1976, 36: 776-782.

16. Corbalan R., Verrier R. L., Lown B. Differing Mechanisms for Ventricular

vulnerability During Coronary Arttery Occlusion and Release.-Am. Heart.

T., 1976, 92: 223-230.

17. Desilva R. A., Verrier R. L., Lown B. Effect of PsychoFic Stress and

sedation with Morphine Sulfate On Ventricular Vulnerability.-Am. Heart J., 1978, 95: 197-203.

18. Liang B. ., Verrier R. L, Lown B. et al. Correlation Between Circulation

catecholamme Levels and Ventricular Vulnerability During Psychologic Stress In Conscius Dogs.-Proc. SOC. EXP. Biol. Med., 1979, 161: 266- 269.

19. Malliani A., Schwartz P. L, Zanchetti A. A Sympathetic Reflex Elicited by

experimental Coronary Occlusion.-Am. J. Physiol., 1969, 217: 703-709.

20. Kelliher G.]., Widmer C, Roberts J. Influence of the Adrenal Medulla

on Cardiac Rhythm Disturbances Following Acute Coronary Arttery Occlu

sion.-Recent. Adv. Stud. Cardiac. Struct. Metab.; 1975, 10: 387-400.

21. Harris A. S., OTERO H., Bocage A. The Induction of Arrhythmias by Sym

pathetic Activity Before and After Occlusion of A Coronary Artery In The

canine Heart.-J. Electrocardiol., 1971,4: 34 -43.

22. Khan M. L, Hamilton J. T ., Manning G. W. Protective Effects of Beta-

aDRENOCEPTOR BLOCKADE IN EXPERIMENTAL OCCLUSION IN CONSCIOUS DOGS.- AM. J. Cardiol., 1972, 30: 832-837.

23. Levy M. N., Blattberg B. Effect of Vagal Stimulation On The Overflow of

norepinephrine Into The Coronary Sinus During Cardiac Sympathetic Ner

vE Stimulation In The Dog.-Circ. RES .. 1976, 38: 81-85.

24. Watanabe A. M., Besch H. R. INTERACTION BETWEEN CYCLIC ADENOSINE MO-

nophosphate and Cyclic Guanosine Monophosphate in Guinea Pig Ventri

cular Myocardium.-CIRC. Res., 1975, 37: 309-317.

25. SURAWICZ B. VENTRICULAR FIBRILLATION.-AM. J. Cardiol., 1971

26. Petropoulos P. C, Jaijne N. G. Cardiac Function During Perfusion Of The

circumflex Coronary Arttery With Venous Blood, Low Molecular Weignt

dextran in Tyrode Solution.-Am. Heart J., 1964, 68: 370-382.

27. Sewell W. M., Koth D. R., HugginsFROM . E. . VENTRICULAR FIBRIRLATION IN DOGS

after Sudden Return of Flow to the Coronary Arttery.-Surgery, 1955, 38

1050-1053.

28. Bagdonas A. A., Stuckey J. H., Piera J. Effects of ISChemia and Hypoxia

on the Specialized Conducting System of The Canine Heart.-Am. Heart.

J., 1961, 61: 206-218.

29. Danese S. Pathogenesis of Ventricular Fibrillation In Coronary Occlusion.

Jama, 1962, 179: 52-53.

30. Kerzner J., Wolf U., Kosowsky B. D. et al. Ventricular Ectopic Rhythms.

fallowing Vagal Stimulation in Dogs with Acute Myocardial Infarction.-

Circulation, 1973, 47: 44-50.

31. Haggins p. IN ., Vainer S. F., Braunwald E. Parasympathetic Control Of

the Heart.-Pharmacol. Rev., 1973, 25: 119-155.

32. Verrier R. L., Lown B. Effect of Left Stellectomy On Enhanced Cardiac

vulnerability Induced by Psychologic Stress (abstr.) .- Circulation, 1977,

56:111-80.

33. Nathanson M. H. Action of Acetyl Beta Methyolcholin On Ventricular

hrythm induced by adrenalin.-proc.SOC. EXP. Biol. Med., 1935, 32: 1297-1299.

34. Cope R. L. Suppressive Effect of Carotid Sinus On Premature Ventricular

beats in Certain Instances.-Am. J. Cardiol., 1959, 4: 314-320.

35. Lown B. ., Levine S. A. The Carotid Sinus: Clinical Value of Its Stimulati

oN.-CIRCULATION, 1961, 23: 776-789.

36. Lorentzen D. Pacemaker-Induced Ventricular Tacycardia: Reversion To

normal Sinus Rhythm by Carotid Sinus Massage.-Jama, 1976, 235: 282-283.

37. Waxman M. In ., Downar E., Berman D. et al. Phenylephrine (NEOSYNE-

phrine R) Terminated Ventricular Tachycardia.-Circulation, 1974, 50:

38. Weiss T. ., Lattin G. M., Engelman K. Vagally Mediated Suppression Of

premature Ventricular CONTRACTIONS IN Man.-AM Heart J., 1975, 89: 700-707.

39. Lown in., Graboys t. IN ., Podrid P. J. et al. Effect of a Digitalis Drug ON

vENTRICULAR PREMATURE BEATS (VPBS) .- N.ENGL. J. Med., 1977, 296: 301-306.

Homeometric heart regulation.

It turned out that the change in heart rate strength depends not only on the initial length of the cardiomyocytes at the end of the diastole. A number of studies show an increase in the reduction force with an increase in the heart rate on the background of the isometric state of the fibers. This is due to the fact that the increase in the frequency of reduction of cardiomyocytes leads to an increase in the content of Ca2 in the sarcoplasm of muscle fibers. All this improves the electromechanical pairing and leads to an increase in the reduction force.

Heart innervation and its regulation.

The modulation of inotropic, chronopopic and drromotropic effects is caused by the sympathetic and parasympathetic departments of the autonomic nervous system. Cardial nerves of VNS consist of two types of neurons. The bodies of the first neurons are located in the CNS, and the bodies of the second neurons form ganglia outside the central nervous system. Preggling fibers of sympathetic neurons shorter postganglyonary, whereas parasympathetic on the contrary.

The effect of parasympathetic nervous system.

The parasympathetic regulation of the heart is carried out by the heart branches of the right and left wandering nerves (x pair of cranial nerves). The bodies of the first neurons are localized in the dasal core of the stray nerve of the oblong brain. The axons of these neurons in the composition of the wandering nerve overlook the skull cavity and are sent to the intramural ganglions of the heart, where the bodies of the second neurons are located. Postgangngling fibers of a wandering nerve in most cases ends on CAR cardiomyocytes and AV knots, atria and an intra-sub-conducted conductive system. At the right and left wandering nerves, a different functional effect on the heart. The region of the distribution of the right and left wandering nerves is not symmetric and overlaps mutually. The right wandering nerve influences mainly on the Ca Node. Its stimulation causes a decrease in the frequency of excitation of the node. While the left wandering nerve has a predominant effect on the AV node. The excitation of this nerve leads to atrioventricular blockades of varying degrees. The action of the wandering nerve on the heart is characterized by a very fast as a response and its termination. This is due to the fact that the mediator of the vaga nerve of the Acetylcholine is rapidly destroyed by acetylcholinecterase, which is much in the Ca and AV nodes. Moreover, acetylcholine acts through specific acetyl-cholin-regulating to "Channels that have a very short latent period (50-100 ms).

Content

Pares of the vegetative system are a sympathetic and parasympathetic nervous system, and the latter has a direct impact and is closely interconnected with the work of the heart muscle, the frequency of myocardial cut. It is localized partially in the head and spinal cord. The parasympathetic system provides relaxation and restoration of the body after physical, emotional loads, but cannot exist separately from the sympathetic department.

What is a parasympathetic nervous system

The department is responsible for the functionality of the body without its participation. For example, parasympathetic fibers provide a respiratory function, adjust the heartbeat, expand blood vessels, control the natural process of digestion and protective functions, provide other important mechanisms. The parasympathetic system is necessary for a person so that the body relates to relax after exercise. With its participation, the muscle tone is reduced, it comes to the norm of the pulse, the pupil and vascular walls are narrowed. This happens without the participation of a person - arbitrarily, at the level of reflexes

The main centers of this autonomous structure - the head and spinal cord, where the nerve fibers are concentrated, providing the highest possible transmission of impulses for the operation of internal organs, systems. With their help, it is possible to control blood pressure, the permeability of vessels, cardiac activity, the internal secretion of individual glands. Each nervous impulse is responsible for a certain part of the body, which when excited it begins to react.

It all depends on the localization of characteristic plexuses: if the nerve fibers are in the area of \u200b\u200bthe pelvis, then they are responsible for physical activity, and in the organs of the digestive system - for the secretion of gastric juice, intestinal peristalsis. The structure of the vegetative nervous system has the following structural departments with unique functions for the entire body. It:

• pituitary;
• hypothalamus;
• nervus vagus;
• epiphiz.

So the main elements of parasympathetic centers are indicated, and the following are the following:

• nervous cores of the occipital zone;
• sacral nuclei;
• heart plexuses to ensure myocardial jolts;
• grated plexus;
• lumbar, curious and chest nervous plexuses.

Sympathetic and parasympathetic nervous system

Comparing two departments, the main difference is obvious. The sympathetic department is responsible for activity, reacts to the moments of stress, emotional excitement. As for the parasympathetic nervous system, it "connects" in the stage of physical and emotional relaxation. Another difference is the mediators that carry out the transition of nerve pulses in synapses: in the sympathetic nerve endings it is norepinephrine, in parasympathetic - acetylcholine.

Features of the interaction of departments

The parasympathetic department of the vegetative nervous system is responsible for the uninterrupted operation of cardiovascular, urogenital and digestive systems, while the parasympathetic innervation of the liver, thyroid gland, kidneys, pancreas occurs. Functions are different, and an integrated effect on the organic resource. If the sympathetic department ensures the excitation of internal organs, then parasympathetic - helps to restore the overall condition of the body. If there is an imbalance of two systems, the patient needs treatment.

Where the centers of the parasympathetic nervous system are located

The sympathetic nervous system is constructively represented by a sympathetic barrel in two rows of nodes on both sides of the spine. Externally, the structure is represented by a chain of nervous lumps. If you affect the element of the so-called relaxation, the parasympathetic part of the vegetative nervous system is localized in the spine and brain. So, from the central departments from the brain, the impulses that occur in the nuclei occur in the composition of the brain-brain nerves, from the sacral divisions - as part of the pelvic internal nerves, reach the bodies of the small pelvis.

Parasympathetic nervous system functions

Parasympathetic nerves are responsible for the natural restoration of the body, the normal reduction in myocardium, muscle tone and productive relaxation of smooth muscles. Parasympathetic fibers are distinguished by a local action, but in the end they act together - with plexuses. With a local defeat of one of the centers, the vegetative nervous system suffers in general. The impact on the body is complex, and doctors distinguish the following useful functions:

• relaxation of the eye nerve, narrowing of the pupil;
• normalization of blood circulation, systemic blood flow;
• restoration of the usual breathing, the narrowing of the bronchi;
• decrease in blood pressure;
• control of an important blood glucose indicator;
• reducing heart rate;
• slowing down the passage of nerve impulses;
• reducing eye pressure;
• settlement of work glands of the digestive system.

In addition, the parasympathetic system helps the vessels of the brain and the genital organs to expand, and smooth muscles come into tone. With it, it takes the natural cleansing of the body at the expense of such phenomena, like a chichanye, cough, vomiting, hiking to the toilet. In addition, if the symptoms of arterial hypertension begin to manifest itself, it is important to understand that the above-described nervous system is responsible for heart activities. If one of the structures is a sympathetic or parasympathetic fail, measures must be taken as closely related to each other.

Diseases

Before using certain medical drugs, research is important to correctly diagnose diseases associated with the impaired work of the parasympathetic structure of the head and spinal cord. The problem with health is manifested by spontaneously, it is able to hit the internal organs, affect the usual reflexes. The following violations of any age can be based on:

1. Cyclic paralysis. The disease is provoked by cycular spasms, strong damage to the glasses. The disease occurs in patients of different ages, accompanied by the degeneration of nerves.
2. Syndrome of the glasses. In such a difficult situation, the pupil can expand without the impact of the flow of light, which is preceded by damage to the afferent area of \u200b\u200bthe zrachkoy reflex arc.
3. Block nerve syndrome. A characteristic disease manifests itself in a patient with a minor squint, imperceptible for a simple man in the street, while the eyeball is directed inside or up.
4. Injured discharge nerves. In the pathological process, the squint is simultaneously combined in one clinical picture, a split view, expressed by Fovilyl syndrome. Pathology affects not only eyes, but also face nerves.
5. Tropro nerve syndrome. Among the main causes of pathology, doctors distinguish increased activity of pathogenic infections, violation of systemic blood flow, damage to cortical nuclear paths, malignant tumors, transferred to the brain injury.
6. Facial nerve syndrome. There is an obvious silence of the face when a person arbitrarily smile, while experiencing painful sensations. It is more often a complication of the suffering disease.