LABORATORY OF PHYSIOLOGY OF RECEPTION

(Headľ acad. A. D. Nozdrachev)

The Laboratory of physiology of reception was founded by the initiative of Academician V. N. Chernigovsky. Since 1972, the Laboratory was headed by Biological Sciences Doctor O. B. Ilyinsky, then by Biological Sciences Doctor G. N. Akoev. In 1999 the head of the Laboratory became Academician A. D. Nozdrachev.

Acad.A.D. Nozdrachev with co-workersat the monument to I.P.Pavlov in St.Petersburg

The main problem studied at these years was connected with analysis of general mechanisms of reception, of mechanisms of information transformation from different mechano- and electroreceptors. It was first discovered that sharks and skates are able, using an electroreceptive apparatus, to perceive weak magnetic fields, including the Earth magnetic field and geomagnetic variations.

The Laboratory staff studies mechanisms of receptor processes on the level of primary afferent nerve conductors in various censor systems. These studies have morpho-physiological direction and are performed with use of electrophysiological, biochemical, immunohistochemical, and immunoenzyme methods.

For the last few years the hypothesis of the existence of neuromodulators has become commonly accepted. Electrophysiological studies of synaptic transmission in receptors of frog semicircular canals have shown that opioid peptides fit a number of requirements for the endogenous neuromodulator in the vestibular system. Mechanism of action of opioid peptides is based on their mediated effect on glutamate receptors. An important role in synaptic transmission is played not only by ionotropic, but also by metabotropic glutamate receptors. The latter are located at pre- and postsynaptic membranes of vestibular organs and participate in modification of synaptic transmission.

A complex study of secretory functions of small intestine is carried out as well as elucidation of the role of interoceptors in regulatory mechanisms of activity of visceral systems providing maintenance of homeostasis of the organism internal medium. The small intestine chemoreceptors have been proven for the first time to essentially contribute to regulatory mechanisms of the pulmonary ventilation activity by providing tuning of the respiratory system activity in correspondence with the tissue metabolism intensity.

An activating action is established of transmitters released by immunocompetent cells during development of immune response on small intestine interoceptors, which has become a ground for suggesting a participation of small intestine sensory structures in modulation of the organism reactions to incorporation of substances of the antigen nature. As a result of the performed study, a concept put forward about participation of the small intestine interoceptors in neuroimmune interactions and in mechanisms of control of basic visceral processes during changes of the organism immune state.

When studying functional properties of neurons of small intestine metasympathetic ganglia the main attention was paid to analysis of Dogel cells of types I and II. These cells were experimentally proven to be sensory neurons able to be activated by action of hydrochloric action on cells of the intestinal wall mucosa. This can be accompanied either by action of serotonin released from enterochromaffin cells on endings of intermuscular plexus multiaxonal neurons or by a synaptic relay with participation of a cholinergic mediator in submucosal or intermuscular plexuses.

The obtained results agree well with a concept of the autonomous principle of development of reflex reactions with participation f functional module neurons of the metasympathetic nervous system.

The problem of regeneration in peripheral parts of the nervous system is actual both in theoretical and in experimental aspects. In the process of searching for factors affecting regeneration processes, biologically active synthetic peptides dalargin and cortagen were studied. The studied peptides have been established to accelerate regeneration processes in damaged nerve fibers. A positive effect on regeneration processes is also characteristic of various biophysical factors including transcranial stimulation of brain opioid structures and action of electromagnet irradiation of the millimeter diapason on the damage area. The obtained data on effects of the central nervous system on regeneration processes in damaged nerve conductors allow concluding that under conditions of disruption of connections with the central nervous system the afferent nervous structures continue functioning and preserve their ability to regenerate after the damage performed simultaneously with decentralization.