At what stage of parabiosis there is no response. Medical aspects of the theory of parabiosis
Many physiological states of humans and animals, such as the development of sleep, hypnotic states, can be explained from the standpoint of parabiosis. In addition, the functional significance of parabiosis is determined by the mechanism of action of some medicines. Thus, this phenomenon underlies the action of local anesthetics (novocaine, lidocaine, etc.), analgesics, and inhalation anesthesia agents.
Local anesthetics(from the Greek. an - denial, aesthesis - sensitivity) reversibly reduce the excitability of sensitive nerve endings and block the conduction of an impulse in the nerve conductors at the site of direct application. These substances are used to relieve pain. Cocaine was first isolated from this group in 1860 by Albert Niemann from the leaves of the South American shrub Erythroxylon coca. In 1879 V.K. Anrep, a professor at the St. Petersburg Military Medical Academy, confirmed the ability of cocaine to cause anesthesia. In 1905, E. Eindhorn synthesized and applied novocaine for local anesthesia. Lidocaine has been used since 1948.
Local anesthetics consist of a hydrophilic and lipophilic part, which are connected by ester or alkyd bonds. The biologically (physiologically) active part is a lipophilic structure that forms an aromatic ring.
Based on the mechanism of action local anesthetics lies a violation of the permeability of fast voltage-gated sodium channels. These substances bind to open sodium channels during an action potential and cause their inactivation. Local anesthetics do not interact with closed channels during the resting potential and channels that are in an inactivated state during the development of the repolarization phase of the action potential.
Receptors for local anesthetics are located in the S 6 segment of the IV domain of the intracellular part of the sodium channels. In this case, the action of local anesthetics reduces the permeability of activated sodium channels. This, in turn, causes an increase in the excitation threshold, and ultimately, a decrease in tissue excitability. At the same time, there is a decrease in the number of action potentials and the rate of conduction of excitation. As a result, in the area of application of local anesthetics, a block is formed for the conduction of nerve impulses.
According to one theory, the mechanism of action of drugs for inhalation anesthesia is also described from the standpoint of the theory of parabiosis. NOT. Vvedensky believed that drugs for inhalation anesthesia act on the nervous system as strong irritants, causing parabiosis. In this case, there is a change in the physicochemical properties of the membrane and a change in the activity of ion channels. All these processes cause the development of parabiosis with a decrease in lability, conductivity of neurons and central nervous system generally.
Currently, the term parabiosis is used in particular to describe pathological and extreme conditions.
Experimental neuroses are an example of a pathological condition. They develop as a result of overstrain in the cerebral cortex of the main nervous processes - excitation and inhibition, their strength and mobility. Neuroses with repeated overstrain of higher nervous activity can proceed not only acutely, but also chronically for many months or years.
Neuroses are characterized by a violation of the basic properties of the nervous system, which normally determine the relationship between the processes of irritation and excitation. As a result, there may be a weakening of the performance of nerve cells, imbalance, etc. In addition, phase states are characteristic of neuroses. Their essence lies in the disorder between the action of the stimulus and the response.
Phase phenomena can occur not only in pathological conditions, but also very briefly, for several minutes, during the transition from wakefulness to sleep. With neurosis, the following phases are distinguished:
Equalizing
In this phase, all conditioned stimuli, regardless of their strength, give the same response.
Paradoxical
In this case, weak stimuli have a strong effect, and strong stimuli have the smallest effect.
Ultraparadoxical
The phase when positive stimuli begin to act as negative ones, and vice versa, i.e. there is a perversion of the reaction of the cerebral cortex to the action of stimuli.
brake
It is characterized by the weakening or complete disappearance of all conditioned reflex reactions.
However, it is not always possible to observe a strict sequence in the development of phase phenomena. Phase phenomena in neuroses coincide with the phases previously discovered by N.E. Vvedensky on a nerve fiber during its transition to a parabiotic state.
Parabiosis Vvedensky
The concept of parabiosis (para- about, bios
Parabiosis- this is a reversible change, which, with the deepening and strengthening of the action of the agent that caused it, turns into an irreversible disruption of life - death
First stage of parabiosis - provisional
Second stage of parabiosis - paradoxical.
The third stage of parabiosis - brake.
Conclusion :
Parabiosis
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"Parabiosis Vvedensky"
Parabiosis Vvedensky
N. E. Vvedensky discovered that excitable tissues respond to the most diverse (ether, cocaine, direct current, etc.) extremely strong influences with a peculiar phase reaction, the same in all cases, which he called parabiosis.
N. E. Vvedensky studied the phenomenon of parabiosis on nerves, muscles, glands, spinal cord and came to the conclusion that parabiosis is a general, universal reaction of excitable tissues to strong or prolonged exposure.
The concept ofparabiosis (para- about, bios- life) was introduced into the physiology of the nervous system by N. E. Vvedensky. In 1901, N. E. Vvedensky's monograph "Excitation, inhibition and anesthesia" was published, in which, based on his research, he suggested the unity of the processes of excitation and inhibition.
Parabiosis- this is a reversible change, which, with the deepening and strengthening of the action of the agent that caused it, turns into an irreversible disruption of life - death
The essence of parabiosis lies in the fact that under the influence of an irritant in excitable tissues, their physiological properties change, first of all, lability decreases sharply.
The classical experiments of N. E. Vvedensky on the study of parabiosis were performed on a neuromuscular preparation of a frog. The nerve in a small area was damaged (alteration) chemicals(cocaine, chloroform, phenol, potassium chloride), strong faradic current, mechanical factor. Then irritated electric shock on the altered part of the nerve or above it.
Thus, the impulses must either originate in the altered segment of the nerve or pass through it on their way to the muscle. Muscle contraction testified to the conduction of excitation along the nerve.
First stage of parabiosis - provisional, leveling, or stage of transformation. This stage of parabiosis precedes the rest, hence its name - provisional. It is called equalizing because during this period of development of the parabiotic state, the muscle responds with contractions of the same amplitude to strong and weak stimuli applied to the section of the nerve located above the altered one. In the first stage of parabiosis, there is a transformation (alteration, translation) of frequent excitation rhythms into rarer ones. All the described changes in the response of the muscle and the nature of the occurrence of excitation waves in the nerve under the influence of irritation are the result of a weakening of the functional properties, especially lability, in the altered area of the nerve.
Second stage of parabiosis - paradoxical. This stage occurs as a result of continuing and deepening changes in the functional properties of the parabiotic segment of the nerve. A feature of this stage is the paradoxical relationship of the altered part of the nerve to weak (rare) or strong (frequent) excitation waves coming here from normal parts of the nerve. Rare waves of excitation pass through the parabiotic segment of the nerve and cause muscle contraction. Frequent waves of excitation are either not carried out at all, as if they fade here, which is observed with the full development of this stage, or they cause the same contractile effect of the muscle as rare waves of excitation, or less pronounced.
The third stage of parabiosis - brake. characteristic feature This stage is that in the parabiotic section of the nerve, not only excitability and lability are sharply reduced, but it also loses the ability to conduct weak (rare) waves of excitation to the muscle.
Conclusion :
Parabiosis is a reversible phenomenon. When the cause that caused parabiosis is eliminated, the physiological properties of the nerve fiber are restored. At the same time, the reverse development of the phases of parabiosis is observed - inhibitory, paradoxical, equalizing.
The presence of electronegativity in the altered area of the nerve allowed N. E. Vvedensky to consider parabiosis as special kind excitation, localized at the site of its occurrence and unable to spread.
PARABIOSIS (parabiosis; Greek para about + biosis life) - a state of excitable tissue that occurs under the influence of strong stimuli and is characterized by a violation of conductivity and excitability.
The term "parabiosis" was introduced in 1901 by the outstanding Russian physiologist H. E. Vvedensky, who first studied and described this condition on nerves and muscles. P. develops under the influence of a wide variety of stimuli (nerve impulses, poisons, drugs in large doses, mechanical, electrical, and other stimuli) on excitable tissues, both in normal conditions and in pathology. At the same time, phases are distinguished: primary (primum), the phase of greatest activity (optimum) and the phase of decreasing activity (pessimum). The third phase combines 3 stages successively replacing each other: leveling (provisional, or transforming, according to H. E. Vvedensky), paradoxical and inhibitory (inhibiting). Each phase is characterized by different parameters.
Phase I (primum) is characterized by a decrease in excitability and an increase in tissue lability. In phase II (optimum), excitability reaches a maximum, and lability begins to decline. In phase III (pessimum), excitability and lability decrease in parallel and 3 stages of P. develop. Stage I (equalizing, in the terminology of IP Pavlov) is characterized by equalization of responses to strong, frequent and moderate irritations; in relation to the strength of stimulation, this stage is called provisional or preliminary, and in relation to the frequency of stimuli - transforming. Stage II is characterized by a perverted response: strong irritations cause less effect than moderate ones (paradoxical stage). I.P. Pavlov also discovered the presence of an ultraparadoxical stage during the development of inhibition in the cortex hemispheres when positive stimuli cause a negative effect, and negative ones cause a positive one (see Higher nervous activity). In stage III, neither strong nor moderate stimuli cause a visible reaction: inhibition develops in the tissue (inhibitory, or inhibitory, stage). However, weak, near-threshold irritations at the beginning of stage III can cause small responses - as if parabiosis is removed.
The deparabiotizing role of such weak stimuli, as well as calcium ions, heat and other stimuli, was studied in detail by students of H.E. Vvedensky N.N. Malyshev (1906), M. I. Vinogradov (1916), L. L. Vasiliev (1925), D. S. Vorontsov, V. S. Rusinov. The facts of the deparabiotizing effect of weak stimuli led L. L. Vasiliev to the concept of "antiparabiosis" and to substantiate the existence of two forms of inhibition - para- and anti-parabiotic, i.e., depolarization and hyperpolarization. After the inhibitory stage, under the action of strong stimuli, a complete loss of excitability and conductivity (block) may occur, and later tissue death.
H. E. Vvedensky compared P. of a nerve with a stopped wave of excitation and designated such a state as local non-oscillatory excitation (according to A. A. Ukhtomsky, stationary excitation).
Before the works of H. E. Vvedensky, the law of power relations dominated in physiology, according to Krom, the reaction is greater, the stronger the irritation. H. E. Vvedensky proved deviations from the law and the existence of the phenomenon of optimum and pessimum in the strength and frequency of stimuli. This law was supplemented in the process of studying the action of weak stimuli: weak stimuli increase the readiness of tissues for subsequent activity, reducing the current activity (activity at the time of action). P.'s discovery and study played an important role in the development of neurophysiology (see), raising for the first time the question of the unity of the main nervous processes - excitation (see) and inhibition (see). Before the works of H. E. Vvedensky and A. A. Ukhtomsky, inhibition was considered as a process fundamentally opposite to the process of excitation. With the proof of the three-phase response and the presence of P. in micro-intervals of time, the unity of the three main nervous processes - excitation, inhibition and rest - became indisputable. Thus, with the adoption of the three-phase nature of P. and the proof of the unity of excitation, inhibition, and rest, such contradictory and difficult problems as parabiotic inhibition and parabiotic local non-oscillatory excitation, the formation of inhibition in the centers on a single stimulation, when a wave of excitation comes, the law “all or Nothing, etc., found an explanation.
The doctrine of parabiosis is a major achievement of domestic science, which has influenced the development of various areas of physiology and theoretical medicine. It contributed to the creation of the concepts of perielectroton, dominant, assimilation of rhythm and amplitude, three-phase response, made it possible to give a fundamentally new assessment of the essence and interconnection of the main nervous processes and the structure of the nerve impulse, representing the unity of the processes of excitation and inhibition and the state of rest.
Bibliography: Vasilyev L. L. Significance of the physiological doctrine of H. E. Vvedensky for neuropathology, JI., 1953; Vvedensky H. E. Complete works, vol. 3-4, JI., 1952-1953; Vinogradov M. I. The teaching of H. E. Vvedensky about the main nervous processes, M., 1952; Voronov Yu. A., etc. The phenomenon of parabiosis in microintervals of time, in the book: Nervous system, ed. J.I. J.I. Vasilyeva, in. 4, p. 23, JI., 1963; Golikov NV Physiological lability and its changes in the main nervous processes, JI., 1950; Latmanizova JI. B. Vvedensky's regularities in electrical activity excitable units, JI., 1949; Ukhtomsky A. A. Collected works - v. 2, p. 54, JI., 1951; At x-tomsky A., Vasiliev L. and Vinogradov M. Teaching about parabiosis, M., 1927; Adrian E. D. Wedensky inhibition in relation to the all or "all-or-none" principle in nerve, J. Physiol. (Lond.), v. 46, p. 384, 1913; Voronov J. A. Problemas de la irritabilidad y los procesos nerviosos fundamentales, v. 1 - 2, Santa Clara, 1969-1973.
Yu. A. Voronov.
Fig. 37- Parabiosis A-Scheme of the experiment of N. E. Vvedensky on the study of parabiosis.A - electrodes for stimulation of the normal (intact) section of the nerve; B - electrodes for stimulation of the "parabiotic part of the nerve"; B - discharge electrodes; G - phone; K 1, K 2, K 3 - telegraph keys; S 1 , S 2 and R 1 , R 2 - primary and secondary windings of induction coils; M - muscle
B-Paradoxical stage of parabiosis. Neuromuscular preparation of a frog with developing parabiosis 43 min after lubrication of a nerve section with cocaine. Strong irritations (at 23 and 20 cm distance between the coils) give quickly passing contractions, while weak irritations (at 28, 29 and 30 cm) continue to cause prolonged tetanuses (according to N. E. Vvedensky)
1. Step back from the electrodes 1 cm towards the Achilles tendon and apply a piece of cotton wool moistened with ether to the nerve. After 8-10 minutes, re-irritate the nerve with a weak, medium and strong current. Despite the increase in the strength of stimulation, the height of muscle contractions remains the same (equalizing phase of parabiosis).
2. With further action of the ether, the excitability and conduction of the nerve decreases, the muscle responds to weak irritation with a large contraction, and to strong irritation with a weak one (paradoxical phase of parabiosis).
3. Finally, there is a complete loss of excitability and conduction of the nerve and the muscle does not respond to a stimulus of any strength (inhibitory phase of parabiosis ). So that the action of the ether does not stop every 2-3 minutes, apply 1-2 drops of ether to cotton wool with an eye dropper.
4. After the third phase of parabiosis, remove cotton wool with ether from the nerve. Rinse it with 0.6% solution sodium chloride. Stimulate the nerve and you will find the restoration of functions, and the phases of parabiosis will go in the opposite direction. Explain the mechanism of parabiosis and draw conclusions:
test questions
1. What is nerve conduction and excitability?
2. Properties of nerve fibers.
3. What is a synapse?
4. Transmission of excitation through the synapse.
5. Laws of excitation.
6. N.E. Vedensky's parabiosis, its phases.
7. Bioelectric phenomena in the body.
8. Currents of rest and currents of action.
R E N I T I E No. 13
CENTRAL NERVOUS SYSTEM,
reflex arc analysis, irradiation, summation, excitation, inhibition
The nervous system regulates the activity of all organs and systems, determining their functional unity, and ensures the connection of the body as a whole with external environment. The structural unit of the nervous system is nerve cell with processes - neuron. The entire nervous system is a collection of neurons that are in contact with each other using special devices - synapses. According to the structure and function, three types of neurons are distinguished: 1. receptor, or sensitive 2. intercalary, closing conductor 3. effector, motor neurons, from which the impulse is sent to the working organs, muscles, glands.
The central nervous system consists of the brain and spinal cord, which, in turn, are formed by many neurons. The most noticeable part of the brain is the cerebral hemispheres, which are the center of higher nervous activity. Their surface is smooth, without furrows and convolutions, characteristic of many mammals. The centers of coordination of instinctive forms of activity are located inside the cerebral hemispheres. The cerebellum is located directly behind the cerebral hemispheres and is covered with furrows and convolutions. His complex structure and large sizes correspond to the difficult tasks associated with maintaining balance in the air and coordinating the many necessary for the implementation of flight and movements.
The body's response to irritation from the external or internal environment, carried out with the participation of the central nervous system, is called a reflex. The path along which the nerve impulse passes from the receptor to the effector, the acting organ, is called the reflex arc. The reflex as an adaptive reaction of the body provides a subtle, precise and perfect balancing of the body with environment, as well as the control and regulation of functions within the body. In this his biological significance. The reflex is a functional unit of nervous activity.
The purpose of the lesson: to explore the composition reflex arc, the role of each component in the implementation of the reflex, the dependence of the time of the reflex on the strength of the stimulus. Familiarize yourself with irradiation, summation, the dominant of excitation, Sechenov's inhibition.
Materials and equipment: frogs, dissecting kits, cotton wool, gauze, induction apparatus, metronome, tripods, 0.1%; 0.5%; 0.3% and 1% sulfuric acid solution, 1% novocaine solution, physiological saline.
“N. E. Vvedensky set his facts mainly
on nerve fiber. We found these facts in the central nervous system.”
NOT. Vvedensky published a book: "Excitation, inhibition and anesthesia", where he showed that living tissue reacts to external stimuli differently, its behavior represents several phases.
The first phase: "Provisional stage" according to N.E. Vvedensky - this is the disappearance of differences in the action of weak and strong rhythmic stimuli (in domestic literature more often they use the name of this phase, given by his student - K.M. Bykov - "equalizing");
The second phase: "Paradoxical stage" according to N.E. Vvedensky - a weak reaction of the tissue occurs to strong irritation, in response to weak irritations - a stronger response than to strong irritation;
Third stage: "Exaltation stage" according to N.E. Vvedensky- loss of the ability of the tissue to respond to irritation (in the domestic literature, the name of this phase, given by K.M. Bykov, is usually used - “inhibitory”).
I note that before the works of N.E. Vvedensky, it was believed that the tissue reacts to external stimulation more or less the same. Here is how the student N.N. Vvedensky:
“The constancy of the reflex reaction was considered such a necessary starting point in analyzes (and only in so far as the arc works constantly, it was such a reliable element for analysis) that people have tendentiously turned a blind eye to the fact that actual reflex arcs, when we experimentally study and stimulate them, can produce extremely varied effects, far from constant and sometimes even directly opposite to what we initially expect from them. The doctrine of reflex perversions arose - “reflex-reversal”, as English physiologists say. The topic of "reflex-reversal" is one of those that has been extremely animated to this day. Here - you feel - we are talking about the fact that the reflex arcs, which we consider to be constantly functioning apparatuses, in some cases - this is accepted as an exception and anomaly - give a deviation from what is supposed to them according to the state, deviations that even reach the opposite. When we talk about “reflex-reversal”, you feel that some kind of norm is accepted, and this norm for each reflex arc is taken as a solid, basic phenomenon, which is opposed to anomalies and perversions. The school I belong to is the professor's school N. E. Vvedensky, does not at all look at perversions of the effect on the same physiological substrate as something exceptional and anomalous. She counts them general rule because she knows that constant reactions on the same substrate are obtained only depending on certain conditions in which we observe a given physiological apparatus - and we also know that when the conditions of stimulation of the same substrate change, as a rule, just like the norm, we get the effect , strongly deviated from the original or even directly opposite to it , i.e., the phenomenon of excitation passes into the phenomenon of inhibition. On the same substrate, depending on several independent variables: firstly, on the quantitative characteristics of the stimulus, namely on the frequency of the stimulus and on its strength, then, on the state of functional mobility in which the reacting device is now, we have effects , naturally passing from excitation to inhibition.
Ukhtomsky A.A., Dominant, M.,–L., "Nauka", 1966, p. 73-74.
And further:
"According to NOT. Vvedensky, inhibition is a kind of modification of excitation: a propagating excitation naturally turns into a non-propagating, stagnant process, or a standing wave (deceleration). This pattern consists in the fact that the higher the rhythm of the influencing impulses and the lower lability of nerve formations, the faster and easier excitation turns into inhibition. Thus, the opposite of these two processes is purely functional, with the same physical and chemical basis.
Kondakov N.I., History of philosophy in the USSR in five volumes, volume III, M., "Nauka", 1968, p. 484.