[Effects of different neuromediators and regulatory peptides on the impulse activity of neurons in the superior vestibular nucleus].

The microelectrode technique and microiontophoresis of physiologically active substances in experiments with cats immobilized with the muscle relaxants made it clear that different classical neuromediators (acetylcholine, norepinephrine, gamma-aminobutyric acid (GABA) and others), as well as regulatory peptides (enkephalins, thyrotropin-releasing hormone (TRH), vasoactive interstitial peptide (VIP), somatostatin (SS) and others) can exert a direct effect on the majority (61 to 100%) of neurons in the superior vestibular nucleus (SVN). The inhibiting effect of enkephalins, VIP and SS on the neurons impulse activity remained essentially unchanged by L-glutamate. Also, enkephalins, VIP and SS were found to amplify the inhibiting action of GABA and glycine. Consequently, these substances can fulfill the role of SVN neuromediators and/or neuromodulators.

[Effects of different neuromediators and regulatory peptides on the impulse activity of neurons in vestibular zone-I of the cerebral cortex].

Microelectrodes and micro-iontophoresis of physiologically active substances in experiments with cats immobilized by muscle relaxants made it apparent that different classical neuromediators (acetylcholine, norepinephrine, GABA and others) and regulatory peptides (enkephalins, thyrotropin-releasing hormone, vasoactive intestinal peptide (VIP), somatostatin (SS) and others) are capable to influence directly 68 to 100% of neurons in vestibular zone-I of the cerebral cortex. In the presence of L-glutamate, the inhibiting effect of enkephalins, VIP and SS on the neurons impulse activity was essentially unaltered. Also it was shown that enkephalins, VIP and SS are potent to augment the inhibiting effect of GABA and glycine. Therefore, these substances may have the neuromediator and/or neuromodulator role in this cortical zone.

[Effects of various neuromediators and regulatory peptides on the impulse activity of neurons in the lateral vestibular nucleus].

The myoelectrode technique and microiontophoresis of physiologically active substances were applied to cats immobilized with neuromuscular relaxant to show that the classic neuromediators (acetylcholine, norepinephrine, GABA etc.) and regulatory peptides (enkephalins, TRHs, vasoactive intestinal peptide (VIP), somatostatin (SS) and others) can influence directly most neurons (58 to 100%) in the lateral vestibular nucleus (LVN). Enkephalins, VIP and SS retained largely their inhibitory effect on the neuron impulse activity in the presence of L-glutamate. Also, enkephalins, VIP and SS are able to stimulate or suppress the inhibitory effect of GABA and glycine. Consequently, the substances under study may act as LVN neuromediators and/or neuromodulators.

[Modification by various neuromediators and regulatory peptides of the impulsation activity of neurons in the medial vestibular nucleus].

Cats were immobilized with myorelaxation agents to apply the microelectrode technique and microlonophoresis of physiologically active substances. As a result it was shown that various classic neuromediators (GABA, taurine and others) and regulatory peptides (vasoactive intestinal peptide (VIP), somatostatine (SS) and others) have effect on the majority (62 to 100%) of neurons in the medial vestibular nucleus. In the presence of L-glutamate VIP and SS CC retained essentially their inhibitory effect on the neurons impulse activity. Both VIP and SS were found to amplify the inhibitory action of GABA and glycine. To sum up, the substances under study can function as neuromediators and/or neuromodulators in the medial vestibular nucleus.

[Antihypoxant effect of zinc(II) bis(N-acetyl-L-cysteinato)sulfate octahydrate in acute normobaric hypoxia].

Using two models of the acute normobaric hypercapnic hypoxia (ANHH) and acute normobaric hypoxia without hypercapnia (ANWH), some parameters of the impulse activity of somatosensory cortex neurons were studied in experiments on cats. A new antihypoxant drug--aminothiol complex substance composed of zinc(II) and N-acetyl-L-cysteine (piQ-1104, 50 mg/kg)--was used for the brain protection. The substance studied showed a high antihypoxant activity in the brain neurons during all stages of both ANHH and AHWH. The average active survival time during hypoxic state was increased 2-2.5 times in comparison to the control group. The neuron activity dynamics under ANHH and AHWH conditions and after piQ-1104 injection was observed.

[Investigation of the anti-motion sickness effect of 3-hydroxypyridine derivatives].

Experiments with rats showed that three out of 12 3-hydroxypyridine derivatives (ethyl-methyl hyd- roxypyrine succinate, SK-132 and IBCP-2 - had an anti-motion sickness effect stronger than of scopolamine, the reference vestiboloprotector. The anti-motion sickness effect of ethyl-methyl hydroxypyrine was also demonstrated in experiments with cats. Apparent anti-motion sickness effect of ethyl-methyl hydroxypyrine (mexydol) was found in 69% of healthy male volunteers which is comparable with the effect of scopolamine (62%). In experiments with immobilized cats (myorelaxation drugs) the microelectrode technique and microontoiphoresis of physiologically active substances revealed that ethylmethyl hydroxypyrine influences the majority of neurons in the medial vestibular nucleus (61%). Suppression of cell spontaneous activities in more than one half of cases can be stopped completely or attenuated significantly by bicucculine, a specific GABA(A)-receptor antagonist. In 42% of neurons ethyl-methyl hydroxypyrine subdues the response to vestibular stimulation which is likely to underlie the anti-motion sickness effect.

Neural correlates of the results-of-action acceptor in a functional biotechnical complex.

This report presents data illustrating the neurophysiological features of efferent-afferent convergence on cortical neurons. During combination of stimulus of pyramidal tract axons with electrocutaneous reinforcement, some of the study neurons were found to change the parameters of their activity evoked by stimulation of this tract: evoked responses started to reproduce the structure of responses to the reinforcement. The most dynamic rearrangements of pyramidal tract responses were obtained in experiments in which the study neurons were included in a biotechnical complex with feedback, the complex consisting of "neuron-computer-stimulator-animal" and actually being an analog of a natural functional system. The role of efferent-afferent convergence on CNS neurons in the development of the results-of-action acceptor of a functional system for a voluntary behavioral act is discussed.

[Neuron correlates of the action result acceptor in a functional biotechnical complex structure]. / Neironnye korreliaty aktseptora rezul'tatov deistviia v sostave funktsional'nogo biotekhnicheskogo kompleksa.

This study presents data illustrating neurophysiological features of the efferent-afferent convergence on the cortex neurons. It was established that, during the process of combining stimulation of the pyramidal tract (PT) axons with electrical skin reinforcement, a significant amount of neurons under study changed parameters of the activity evoked by the PT-stimulation. The most clear reconstruction of the PT-responses was obtained in experiments with inclusion of neurons into biotechnical complex by means of the feed back: "neuron-computer-stimulating devices-animal", representing an analogue of the functional system. The role of afferent-efferent convergence of the CNS neurons is discussed in dynamic deployment of the action result acceptor in the functional system of natural behavioural act.

[Effect of nootropic agents on impulse activity of cerebral cortex neurons]. / Vliianie nootropov na impul'snuiu aktivnost' neironov kory bol'shogo mozga.

The effect of nootropes (semax, mexidol, and GVS-111) on the activity of individual neurons in various cerebral cortex regions was studied by microelectrode and microionophoresis techniques in cats immobilized by myorelaxants. It was established that the inhibiting effect of mexidol upon neurons in more than half of cases is prevented or significantly decreased by the GABA antagonists bicuculline and picrotoxin. The inhibiting effect of semax and GVS-111 upon neurons in more than half of cases is related to stimulation of the M-choline and NMDA receptors, respectively.

[Movement disorders in the context of P.K. Anokhin's theory of functional systems]. / Bolezn' dvizheniia s pozitsii teorii funktsional'nykh sistem P.K. Anokhina.

The authors' own findings and the data available in the literature as to movement diseases (MD) in animals and man were reviewed in the context of P. K. Anokhin's theory of functional systems. The functional system of the human body's gravity center is detailed. There is evidence for that disintegration processes underlying MD first occur in the mnestic sphere since due to genetic and/or ontogenetic causes, memory has no preserved no motor programme required to achieve the end net efficiency of performance of this functional system,--to maintain the definite position of the gravity center of the body and its related vegetative status upon stress-induced vestibular exposures. Based on the above concepts of the pathogenesis of MD, its preventive measures have been proposed and tested, which include drug (nootropic agents) and non-drug (a special complex of physical exercises for children aged 2 to 7 years, which will form permanent motor programs in memory in definite periods of their ontogenesis) measures.

[Efferent-afferent convergence as a structural-functional basis for a mechanism of an acceptor of action results]. / Efferentno-afferentnaia konvergentsiia kak strukturno-funktsional'naia osnova apparata aktseptora rezul'tatov deistviia.

In investigation data illustrating neurophysiological features efferent-afferent convergence in CNS are presented. Possibility of involvement of the efferent-afferent convergence mechanism in development of the acceptor of action results apparatus is considered. The role of parietal associative cortex as the integrative zone and zone of interaction the collateral pyramidal excitations with the nature afferent excitations is also discussed. The functional role of efferent-afferent convergence and interaction within the cyclic outline: motor cortex-parietal associative cortex-caudate nucleus-pallidum-thalamus-frontal cortex-motor cortex is analysed.

[The spontaneous and evoked neuronal activity of the parietal associative cortex in cats during motion sickness]. / Spontannaia i vyzvannaia aktivnost' neironov temennoi assotsiativnoi kory u koshek v protsesse ukachivaniia.

In the experiments with the cats a spontaneous and induced activity of the neurons (57) of parietal associated cortex during motion sickness was studied. It was found that after a 15 min motion sickness 54 percent of the examined neurons displayed suppression, 20 percent of neurons did an increase of spontaneous activity. Twenty-six percent of neurons did not respond to motion sickness. The dynamics of induced neuronal responses under motion sickness effect was complex, a direction of the changes in induced responses frequently did not agree with that of alterations in a spontaneous cellular activity. The more stable changes of induced responses have been in the neurons with phase responses to the fight and electrocutaneous stimulation. After 45-min effect of motion sickness, the light-stimulated responses were characterized by an increase of early and suppression of late components of a response, and the responses to electrocutaneous stimulation displayed mainly a suppression of the early components of the responses.

[Effects of oxiracetam and piracetam on the electrical activity of neurons of the cerebral cortex]. / O vliianii oksiratsetama i piratsetama na élektricheskuiu aktivnost' neironov kory golovnogo mozga.

The effect of oxiracetam and piracetam on the spontaneous impulse neuronal activity of the somatosensory cortex of the cat and rabbit was studied. Oxiracetam and piracetam when applied microiontophoretically changed neuronal activity by depressing in the majority of the cases studied or sometimes facilitating the spontaneous firing rate. A small percentage of neurons (about 30%) remains unaffected by the application of the nootropics. In some cases oxiracetam and piracetam diminished the depress effect of morphine and DADLE on the spontaneous impulse neuronal activity.

[Effects of enkephalins on associative processes of parietal cortex neurons]. / Vliianie énkefalinov na assotsiativnye protsessy neironov temennoi kory.

Experiments on cats examined the effect of met- and leu-enkephalins on the process of learning of the parietal associative cortex neurons (field 5). It has been shown that conditioned electrical stimulation of the pyramidal tract axons with nociceptive reinforcement evoked plastic changes of responses in 35 neurons. It was found that the effect of microiontophoretically applied enkephalins on these neurons depend on the time of iontophoretic application. When endogenous opioid peptides were applied up to 30-40 min they inhibited the process of elaboration of temporary connection.