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Biomedical subjects

S A Chepurnov

Publications and source records attributed to S A Chepurnov.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Efferent sympathetic activity after stimulation of the amygdaloid nuclei of the rat brain].

Efferent sympathetic activity (ESA) recorded from cervical sympathetic trunk, was augmented after stimulation of medial, cortical and basal amygdaloid nuclei, whereas stimulation of the lateral amygdaloid nuclei decreased the ESA. Stimulation of the dorsal hippocampus also decreased the ESA. Electrolytic lesion of the septum led to an increase of the ESA during simultaneous stimulation of the lateral amygdaloid nucleus and the dorsal hippocampus. The data suggest that functional interaction between amygdaloid nuclei and septal relays participate in the amygdaloid influence on the activity of preganglionic sympathetic neurons.

Amygdala↗
PubMed1984

[Reactions of neurons of the anteromedial hypothalamus to microiontophoretic administration of luliberin].

The effects of microiontophoretic application of luliberin (LHRH), norepinephrine (NEO) and morphine on activity of the medial preoptic hypothalamic neurons were studied in male rabbits. About 80% of all the neurons responded to LHRH, mainly with facilitation. NEO appeared to have inhibitory influence on the LHRH-induced effects, when LHRH was applied simultaneously with NEO. Since the LHRH effect might be mediated via opiate receptors, it was examined against the background of morphine application. LHRH applied after morphine increased the number of unresponsive units. During simultaneous application of LHRH and morphine the number of unresponsive units increased by 30% and the number of facilitation responses decreased to 30% of the neurons under study. These findings confirm that the opiate receptors and noradrenergic system play a certain role in the central effects of LHRH.

Animals↗
PubMed1983

[Effect of melanostatin on the central nervous system].

The effect of melanostatin (MIF), L-DOPA and morphine on the behaviour and electrical activity in the neocortex and lymbic structures in rats has been strudied. All substances were administered intraventricularly. There was a recorded increase of the energy of the delta and theta slow waves in the hypothalamus, amygdala and neocortex and also of the energy of the alfa waves in the amygdala and neocortex. In addition the administration of L-DOPA and morphine facilitated the effect of MIF while preliminary administration of MIF blocked the effect of morphine given in threshold doses.

Animals↗
PubMed1983

[Evoked potentials in the rabbit amygdala following its partial deafferentation].

The EPs in the rabbit Amygdala were recorded after chronic (5 weeks) deafferentation following section of stria terminalis, commissura anterior and the ipsilateral frontal lobe cortex. Stimulation of the bulbar olfactory regions caused some facilitation of the EPs in non-olfactory nucleus of amygdala. Following ventromedial hypothalamic stimulation, the EPs remained unchanged in the caudal parts, diminished in the rostral parts of basolateral amygdala and disappeared in the medial nucleus of amygdala.

Amygdala↗
PubMed1982

[Effect of somatostatin on neurons of partially deafferented amygdala in the rabbit].

Responses of 291 neurons to microelectrophoretically injected somatostatin were studied in the amygdala of rabbits under nembutal anesthesia. Both excitatory and inhibitory effects were found in contrast to earlier data on the only inhibitory reactions in hypothalamic neurons. After partial chronical deafferentation of the amygdala responses to somatostatin application were observed in 76% of the registered neurons, 90% of these neurons with background discharge frequency from 6 to 20 imp/s, responded by an increase in their activity, while inhibitory reactions were recorded in neurons with average background discharge frequency above 20 imp/s. Since amygdaloid neurons exert a regulating effect on the secretion of the growth hormone through somatostatin, it is suggested that the observed responses reflect one of their feedback mechanisms.

Afferent Pathways↗
PubMedDate not supplied

The pre-Bötzinger complex participates in generating the respiratory effects of thyroliberin.

Experiments on anesthetized rats were performed to study the effects of microinjection of thyroliberin (10 fM-100 microM) into the area of the pre-Bötzinger complex on respiratory and circulatory parameters. Thyroliberin dose-dependently increased respiration frequency, with shortening of inspiration and expiration. Tidal volume and the amplitude of the integrated EMG recorded from the inspiratory muscles decreased after administration of concentrated solutions. Using this dosage method, thyroliberin had weak effects on systemic hemodynamics. The data suggest that structures located in the area of the pre-Bötzinger complex take part in generating the respiratory effects of thyroliberin.

Animals↗
PubMedDate not supplied

Peptidergic mechanisms of hyperthermia-evoked convulsions in rats in early postnatal ontogenesis.

This report addresses the verification of the hypothesis that arginine-vasopressin affects the formation of hyperthermia-evoked convulsions in early ontogenesis in rats on days 3, 5, 7, and 9 of postnatal life. The modification of experimental febrile convulsions by PACAP (pituitary adenylate cyclase-activating peptide) was investigated; PACAP is a physiological regulator of the neurosecretion of arginine-vasopressin. Arginine-vasopressin (10 microg/rat) and PACAP (0.01 microg/rat) decreased the latency of generalized tonic-clonic convulsions and the time of truncal generalization of convulsive activity on days 3 and 5 of rat development. Animals given arginine-vasopressin (0.1-10 microg/rat) sowed significant increases in the duration of generalized convulsions to the level of status epilepticus on day 9 of life. Conversely, administration of higher doses of PACAP (0.1 microg/rat) increased the threshold of tonic-clonic convulsions on days 3 and 5 and decreased it on days 7 and 9 of postnatal development. The indirect involvement of PACAP in the mechanisms of experimental febrile convulsions is suggested to act via changes in arginine-vasopressin neurosecretion.

Animals↗
PubMedDate not supplied

[Pituitary adenylate cyclase activating peptide (PACAP)--its polyfunctionality in the mechanisms of brain protection].

Modern data of molecular and biological properties and physiological role of new pituitary adenylate cyclase activating polypeptide--PACAP--review. PACAP play key role in the embryogenesis of brain, in the protection of brain nerve cells from ischemia-induced death, injuring and apoptosis. New data are discussed concerned with molecular cloning and tissue distribution of receptors for PACAP, gene proPACAP expression in gastrointestinal tract, reproductive organs and nervous system. PACAP increase cytosolic free calcium and modifies the calcium-sensitive K(+)-channels, PACAP protects cultures cortical and hippocampal neurons from glutamate-induced cytotoxicity. The sleep modulation and modification of seizures activity of brain through the secretion of vasopressin or/and through NMDA receptors directly should be include in the program of PACAP "physiological continuum" of functions.

Amino Acid Sequence↗
PubMedDate not supplied

[Anxiety and behavior in WAG/Rij strain rats with genetically induced absence attacks].

Behavior of nonlinear rats and animals from Wistar and WAG/Rij (with inborn generalized absence epilepsy) strains was examined in the elevated plus-maze and the hole board. WAG/Rij rats demonstrated low exploratory behavior in both tests. In the elevated plus-maze, WAG/Rij rats were more balanced and more anxious than Wistar and nonlinear rats. Administration of ethosuximide completely eliminated spike-wave discharges but did not change behavioral interstrain differences. Since the spike-wave patterns develop in WAG/Rij at the age of 3 months, the behavior of young (2-moth-old) pups from different strains was compared and significant differences were revealed. Correlation between the genetically defined features (spike-wave discharges) and behavioral peculiarities in WAG/Rij rats is supposed.

Aging↗