[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.

[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.

[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.

[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.

[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%).

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.

[Neuron correlates of the action result acceptor in a functional biotechnical complex structure].

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.

[Effect of nootropic agents on impulse activity of cerebral cortex neurons].

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.

[Efferent-afferent convergence as a structural-functional basis for a mechanism of an acceptor of action results].

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.

[Movement disorders in the context of P.K. Anokhin's theory of functional systems].

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 spontaneous and evoked neuronal activity of the parietal associative cortex in cats during motion sickness].

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.

[Effects of oxiracetam and piracetam on the electrical activity of neurons of the cerebral cortex].

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.

[Effects of enkephalins on associative processes of parietal cortex neurons].

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.

[Neurophysiological analysis of efferent-afferent interaction of neurons of the parietal associate cortex in cats].

Neuronal responses of the parietal associate cortex (field 5) was recorded in waking cat during electrical stimulation of the pyramidal tract axons and afferent stimulation. The electrical stimulation of the pyramid evoked marked responses in 39% of neurons. 87% of these neurons increased spike activity during sematic nociceptive stimulation, 61% of test neurons were activated by light or tonal stimulation.

[Chemical sensitivity of the neurons of the medial vestibular nucleus to enkephalins, acetylcholine, GABA and L-glutamate].

The effect of enkephalins, morphine and some neurotransmitters on spontaneous and evoked activity of neurons of the medial vestibular nucleus was investigated. The evoked activity was produced by an adequate stimulation of the vestibular apparatus. It was shown that neurons of this nucleus were highly sensitive to enkephalins, morphine, acetyl choline, GABA and L-glutamate (approximately 80% of the nerve cells were inhibited or excited in response to the micro-iontophoretic application of these substances).

[Effect of beta-neo-endorphin--an agonist of chi-opiate receptors on the neuronal activity of the cerebral cortex].

Experiments on cats were made to examine the neuronal responses (the first zone of the somatosensory cortex and the 5th region of the parietal associative cortex) to microapplications of beta-neo-endorphine (an agonist of kappa-opiate receptors), morphine (an agonist of mu-opiate receptors), leuenkephalin (an agonist of delta-opiate receptors) and beta-endorphine (an agonist of mu, delta, epsilon-opiate receptors). beta-Neo-endorphine and other opioid peptides produced similar depressive changes in spontaneous activity. Naloxone in doses which block the depressive reactions of morphine, leu-enkephalin and beta-endorphine did not remove the depressive reactions of beta-neo-endorphine.

[Effect of beta-endorphin, enkephalins and their synthetic analogs on the neuronal electrical activity of the respiratory center in the medulla oblongata].

It has been shown in experiments on conscious rabbits that beta-endorphine, enkephalins and their synthetic analogs as well as morphine suppress respiration depending on the dose. Naloxone completely reverses this effect of the drugs. While studying the mechanism of the suppressing action of morphine-like substances on respiration in experiments on anesthesized rabbits and cats, opioid peptides and morphine were applied microiontophoretically to the neurons of the bulbar respiratory center.

[Effect of opioid peptides, morphine and electroacupuncture on the neuronal activity of the sensorimotor cortex and brain stem reticular formation].

Experiments were made on unanesthetized rabbits and cats to examine the neuronal response (the sensomotor cortex, mesencephalic reticular formation, giant cell reticular nucleus of the medulla oblongata) to microapplications of enkephalins, endorphins, morphine, and electroacupuncture. Opiate peptides, morphine, and electroacupuncture produced similar, unidirectional changes in both spontaneous and nociceptive-stimulated neuronal activity. Naloxone removed these reactions.