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Biomedical subjects

V P Belyĭ

Publications and source records attributed to V P Belyĭ.

At least 19 recordsLinked to original sources
PubMed1987

[Changes in the duration of pauses between self-stimulations in response to cortisol].

Intraperitoneal administration of glucocorticoid hormone cortisol (10 mg/kg) decelerated the self-stimulation (SS) frequency within 5-7 min. The maximal effect occurred within 10 to 20 min. Histograms of pauses duration between SS revealed a shift of mean values from 2.0-2.5 to 4-6 sec. A sharp increase of long pauses transformed chiefly mono- modal forms of control histograms into bimodal those under the hormonal effect. Behaviourally this was manifested by occurrence of burst type of SS responses when series of uninterrupted instrumental responses alternated with prolonged pauses between them. The data obtained are considered from the stand-point of systemic approach to analysis of organization of willed behaviour and role of cortisol in central mechanisms of positive reinforcement.

Animals↗
PubMed1986

[Effect of cortisol on a model of stereotypical behavior in the rabbit in the form of hindlimb thumping].

A 5-sec electrical shock applied to the rabbit medial hypothalamus induced series of stereotype behavioral responses in the form of synergic blows with hindlimbs. Adaptation to the stimulation occurred in repetition of the stimuli every 1.5-2.0 min. Pharmacological experiments revealed that intraperitoneal administration of cortisol (10 and 20 mg/kg) enhanced the stimulation-induced behavioral response and shortened its latency.

Animals↗
PubMed1984

[Role of noradrenaline in the synaptic processes in individual hippocampal neurons under self stimulation].

In response to electrical self-stimulation of the hypothalamus, 5 out of 22 neurons of the hippocampus (fields CA2, CA3, dentate fascia) were inhibited and 9 neurons were activated. Micro-iontophoretic application of noradrenaline weakened the activation response and had no obvious effect on the inhibitory responses. The data obtained disagree with the noradrenergic hypothesis of positive reinforcement mediation (at the level of the brain hippocampal structures).

Animals↗
PubMed1982

[Effect of the "memory peptide" ACTH 5-10 on the self-stimulation reaction of rabbits].

Experiments on rabbits were made to study variation in the frequency of the self-stimulation reaction from the lateral hypothalamus under the effect of the corticotropin fragment ACTH5-10. Intraperitoneal administration of the peptide in a dose of 50 micrograms/kg that causes the improved training in different behavioral models produces no significant effect on the mechanism of intracranial positive reinforcement. Intraventricular injection of 5 microliters of 0.9% NaCl leads to a short-term suppression of the self-stimulation reaction. Administration of 50 pcM/kg ACTH5-10 in the same volume of physiological saline completely abolishes the inhibitory action of the intraventricular injection itself.

Adrenocorticotropic Hormone↗
PubMed1981

[Effect of microapplications of cholecystokinin octapeptide on neurons of the dorsal hippocampus of alert rabbits].

The hormonally active fragment of the intestinal hormone cholecystokinin applied microiontophoretically or under pressure to the hippocampal neurons (fascia dentata and CA3 field) more or less depressed their spontaneous firing rate depending on the dosage. The neurons sensitivity to L--glutamate did not essentially change, at that. Neurons with burst--like firing started to reveal a regular patterns of firing. These data suggest an important role of the cholecystokinin octapeptide in central mechanisms of positive reinforcement.

Action Potentials↗
PubMed1981

[Changes in the pattern of hippocampal neuron discharge as a reflection of the reinforcement effect in self-stimulation].

Changes of the unit activity patterns occurred in the rabbit dorsal hippocampus after self-stimulation. The changes occurred mostly in the theta-burst neurons and in neurons with reduction of spike amplitudes within each burst of discharges. Spontaneous activity of these neurons revealed bimodal histograms of interspike interval distribution. Within 1--3 sec after the self-stimulation the burst-type activity transformed into the regular or arrhythmic one with monomodal form of histogram. Spontaneously regular and arrhythmic neurons revealed no change of patterns. The findings corroborate the Grshtian hypothesis that the reward effect in self-stimulation is correlated with the motor rebound-effect. Experiments with cessation of reinforcing stimulus suggested a dependence of the burst-type pattern of discharges of the hippocampal neurons on the functional state of expectancy of the reinforcing stimulus.

Animals↗
PubMed1981

[Cortisol weakening of hippocampal neuron response during self stimulation].

In unrestrained rabbits, the majority of dorsal hippocampus' neurons changed their firing rate immediately after cessation of electrical stimulation of the lateral hypothalamus. Microionophoretic application of cortisol inhibited the excitatory responses selectively and intensified the inhibitory responses unspecifically. Cortisol seems to affect the hippocampal neurons via different mechanisms depending on the level of their excitability and the transmitters involving them into the integrative function of the positive reinforcement.

Animals↗
PubMed1980

[Qualitatively similar effects of microiontophoretic applications of corticotropin and hydrocortisone in the hippocampal and hypothalamic neurons of rabbits].

A comparison was made of the responses of hypothalamic, septal and hippocampal neurons to microionotophoretic applications of corticotropin (ACTH) and hydrocortisone. A reliable positive correlation of medium significance was found in the hippocamp, less pronounced positive correlation in the hypothalamus and no correlation in the septum. The data obtained indicate that the hippocampal and hypothalamic brain structures are characterized by functional similarity of the mechanisms of neuronal sensitivity to each hormonal substance. It is unlikely that the neurophysiological processes participating in the response of nervous cells to ACTH and hydrocortisone applications are similar, this suggestion being supported by the presence of a number of exceptions and absence of the correlation in the septum.

Adrenocorticotropic Hormone↗
PubMed1980

[Effect of microiontophoretic applications of cortisol on hippocampal neuronal activity in experiments on freely moving rabbits].

In response to cortisole administration the majority of hormonesensitive hippocampal neurons increased ther firing rate in unrestrained rabbits. Apart from this, the hormone affected the interspike intervals distribution. Neurons with a lower spontaneous firing rate revealed a trend towards raise of hormone sensitivity. The data obtained corroborate the inhibitory role of the dorsal hippocampus in central mechanisms of regulation of hypophyseal corticotropic activity by the corticoids level.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[The conditioned-reflex mechanism of the development of tolerance for and dependence on narcotic agents].

At the beginning the term "tolerance" determinations, given in different source of literature, have been considered. Further, the history of conditioned of tolerance and abuse creation from psycho-active drugs have been discussed. The hart of the article contains the critical points of the current representation of neurophysiological theory in the field of behavior, interaction mechanisms between live systems and drugs. The point of view, dominating in pharmacology science that tolerance is the direct result of drug substances intervention into the organism, has been opposed. Separation of primary and secondary physiological effects of drugs, allowed to the authors to conclude that the dominant role belongs to the state living system and to the presence of necessities during the motivation creations for the second drug use and to the tolerance changing.

Animals↗
PubMedDate not supplied

[The role of visual stimuli in the acquisition of place preference with morphine reinforcement].

In experiments with rats was studied the role of visual stimuli in conditioning of place preference in a T-shaped chamber, certain stimuli being combined with morphine injection (5 mg/kg). Intensity of illumination of the chamber sections, colour of walls, and the orientation of dark stripes on the walls were varied. Testing the animals' behaviour began with determining the reward properties of certain visual stimuli on the basis of the total time of the animals' stay in a chamber. Procedure of combining the visual stimuli with morphine was repeated four times. Associative properties of the stimuli were revealed by comparing the learning efficiency in different experimental groups. Learning within the framework of the place preference model was concluded to depend upon the reward properties of the visual stimuli, whereas the behaviour itself to be based on the mechanism of the instrumental but not the classical conditioned response.

Acoustic Stimulation↗
PubMedDate not supplied

[Inhibitory effect of hydrocortisone and corticotropin on the self stimulation reaction].

The effect of hydrocortisone and ACTG on the frequency of self-stimulation reaction (SS) was studied. It was shown that hydrocortisone markedly suppresses the central mechanism of the positive reinforcement. SS frequency is lowered 10-15 minutes after the drug administration and recovered in one hour. The changes in the frequency of SS in response to ACTG are simular to the hydrocortisone effect, but are less intensive and in some cases depend on the location of the stimulating electrodes.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Relation between the dynamics of the extinction process and the initial rate of hypothalamic self-stimulation in the rabbit].

In experiments on rabbits with electrodes chronically implanted in the lateral hypothalamus, dynamics was studied of extinction of self-stimulation reaction as a result of cancellation of intracerebral reinforcement. General dynamics of extinction of the unreinforced instrumental actions and behavioural manifestations of orienting-investigating reaction were revealed. It was found, that in 30% of rabbits, the orienting reaction appearing as a result of "discordance" between expected and actual afferentation is attended by a species-specific form of behaviour, expressed in the form of hind paws synergic strokes against the floor. It is suggested that these strokes may be a somatic expression of a negative emotional state of animals during self-stimulation extinction. The comparison of extinction dynamics with the level of self-stimulation background frequency showed a relative independence of the strength of drive towards getting positive emotions on motivational effects created by electric stimulation of the reinforcing brain structures.

Animals↗