From Big Medical Encyclopedia

PARABIOSIS (parabiosis; Greek para near + biosis life) — the condition of excitable fabric arising under the influence of strong irritations and which is characterized by disturbance of conductivity and excitability.

The term «parabiosis» is entered in 1901 by the given Russian physiologist of H. E. Vvedensky who for the first time studied and who described this state on nerves and muscles. The item develops at action on excitable fabrics of the most various irritants (nervous impulses, poisons, drugs in high doses, mechanical, electric and other incentives) as is normal, and in pathology. At the same time allocate phases: primary (primum), phase of the greatest activity (optimum) and phase of decrease of the activity (pessimum). The third phase combines 3 stages which are consistently replacing each other: leveling (provisional, or transforming, on H. To E. Vvedensky), paradoxical and brake (braking). Each phase is characterized by various parameters.

The I phase (primum) is characterized by decrease in excitability and increase in lability of fabric. In the II phase (optimum) excitability reaches a maximum, and lability begins to decrease. In the III phase (pessimum) excitability and lability decrease in parallel and 3 stages of the Item I a stage develop (leveling, on I. P. Pavlov's terminology) it is characterized by alignment of answers to strong, frequent and moderate irritations; in relation to power of irritation this stage is called provisional or preliminary, and in relation to the frequency of incentives — transforming. The II stage is characterized by the perverted reaction: strong irritations cause smaller effect, than moderated (a paradoxical stage). I. P. Pavlov existence also an ultraparadoxical stage was revealed at development of braking in bark of big hemispheres when positive irritations cause negative effect, and negative — positive (see. Higher nervous activity ). In the III stages strong, moderate irritations do not cause visible reaction: braking develops in fabrics (brake, or braking, a stage). However weak, at - threshold irritations at the beginning of the III stage can cause small answers — as if remove a parabiosis.

The Deparabiotiziruyushchy role of such weak irritations, and also calcium ions, heat and other irritants was in detail studied by pupils of H. E. Vvedensky N. N. Malyshev (1906), M. I. Vinogradov (1916), L. L. Vasilyev (1925), D. S. Vorontsov, V. S. of Russia-new. The facts of deparabiotiziruyu-shchy action of weak irritants led L. L. Vasilyev to the concept of «anti-parabiosis» and to justification of existence of two forms of braking — couple - and anti-parabiotic, i.e. depolyari-zatsionny and giperpolyarizatsionno-go. Behind a brake stage at action of strong irritants there can occur total loss of excitability and conductivity (block), and further and dying off of fabric.

H. E. Vvedensky compared P. of a nerve to the stopped excitation wave and designated such state as local not oscillatory excitement (according to A. A. Ukhtomsky stationary excitement).

Before works of H. E. Vvedensky in physiology the law of the power relations dominated, according to Krom reaction of subjects is more, than the irritation is stronger. H. E. Vvedensky proved deviations from the law and existence of the phenomenon of an optimum and pessimum of force and frequency of irritations. This law was added in the course of the research of action of weak irritations: weak irritations increase readiness of fabrics for follow-up activity, reducing the current activity (activity at the time of action). Opening and a research P. played an important role in development neurophysiology (see), having raised for the first time a question of unity of the basic nervous processes — excitement (see) and braking (see). Before works of H. E. Vvedensky and A. A. Ukhtomsky braking was considered as the process essentially opposite to process of excitement. With the proof of three-staging of reaction and P.'s presence in microtime slices there was indisputable a unity of three basic nervous processes — excitement, braking and rest. Thus, with adoption of three-staging of P. and the proof of unity of excitement, braking and rest such contradictory and difficult problems as parabiotic braking and parabiotic local not oscillatory excitement, formation of braking in the centers on single irritation when the excitation wave, the law «everything or nothing», etc. comes, found an explanation.

The doctrine about a parabiosis is the large achievement of domestic science which exerted impact on development of various fields of physiology and theoretical medicine. It promoted creation of concepts of a perielektroton, dominant, assimilation of a rhythm and amplitude, three-phase reaction, allowed to give essentially new assessment to essence and interrelation of the basic nervous processes and the structure of nervous impulse representing unity of processes of excitement and braking and a condition of rest.

Bibliography: Vasilyev L. L. Value of the physiological exercise H. E. Vvedensky for neuropathology, JI., 1953; Vvedensky H. E. Complete works, t. 3—4, JI., 1952 — 1953; Vinogradov M. I. Doctrine H. E. Vvedensky about the basic nervous processes, M., 1952; Yu. A. Ravens, etc. The phenomenon of a parabiosis in microtime slices, in book: A nervous system, under the editorship of JI. JI. Vasilyeva, century 4, page 23, JI., 1963; N. V Brooms. Physiological lability and its changes at the basic nervous processes, JI., 1950; Latmanizova JI. B. Vvedensky's patterns in electric activity of excitable units, JI., 1949; Ukhtomsky A. A. A collection of compositions - t. 2, page 54, JI., 1951; At x - Tomsk And., Vasilyev L. and Vinogradov M. The doctrine about a 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.