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Biomedical subjects

S A Chepurnov

Publications and source records attributed to S A Chepurnov.

At least 19 recordsLinked to original sources
PubMed1998

[Pre-Bötzinger complex participates in respiratory effects of thyroliberin].

Responses of the TRH microinjections into the pre-Bötzinger complex of adult anesthetised rats involved a dose-dependent increase in respiratory rate as well as shortening of inspiratory and expiratory duration. The tidal volume and inspiratory muscles' activity decreased following high concentrations of the TRH. The heart rate did not change. The findings suggest that the pre-Bötzinger complex is at least partly responsible for the TRH tachypnoic effect.

Animals↗
PubMed1994

[Role of neuropeptides in the lateralization of brain (as exemplified by behavior in radial maze].

The effects of thyroid-releasing hormone (TRH) and substance P (SP) on rat brain lateralization have been studied by three test methods: T-maze, 12-arm radial maze (r. m.) and rotometry. The animals were given 415 micrograms/kg of TRH i. p. or 25 micrograms/kg of TRH intranasally or 50 micrograms/kg of SP i. p. The number of errors and time of task solution in r. m. decreased in the first day of TRH administration. Simultaneously, left-sided deviations in maze-arm choices appeared in some rats' strategy, which made successive arm choices possible. SP induced search activity in rats at the stage of acquisition, yet SP given in the period of tolerant r. m. performance caused degradation of short-time memory and right-sided lateralization appeared.

Animals↗
PubMed1992

[Thyroliberin: new physiological effects and prospects of clinical use].

In addition to the well-known activities of TRH (stimulation of respiration, antidepressant action, increase of motility, antishock action, therapeutic effects against ataxia, and so forth), some new properties were established. TRH was found (1) to stimulate the contractility of lymph vessels in ultra-low doses and to be useful in the treatment of acute pancreatitis; (2) to normalize cerebral circulation in rats and neonates after asphyxia; (3) to improve the electrophysiological parameters of the retina and pigmented epithelium in rats and man, to exert a long-term positive influence on the health status of patients suffering from senile retinal macular dystrophy; (4) to potentiate the analgesic effect of low doses of morphine in a definite range of doses (analog PR-546). It is of paramount importance that most of the indicated activities of TRH may hold promise for clinical application.

Acute Disease↗
PubMed1991

[An increase in brain temperature in rats to the intranasal administration of thyroliberin].

The integral rat brain temperature was measured by radiothermoscope after intranasal instillation of thyroliberin in a dose 400 mkg. The recording increase of temperature lasted during two hours after instillation. This phenomenon is based both on the direct action of thyroliberin and on its capacity to stimulate the induction of other regulatory peptides.

Administration, Intranasal↗
PubMed1989

[Thyroliberin-induced motor asymmetry as an indicator of the individual behavioral strategy of rats in a radial labyrinth].

The individual peculiarities of functional changes in motor asymmetry determined by behavioral test in T-maze have been shown in experiments with rats (nonpedigree and line LATI). The application of thyroliberin (10 mkg/kg) causes and increases the left-side lateralization which introduces alteration in the individual strategy of the successive round of 12 rays of radial maze with food during solution of spatial orientation task.

Animals↗
PubMed1989

[Cascade unidirectional regulatory processes implemented by short-lived peptides (thyroliberin)].

Long-term physiological effects of the short-lived regulatory peptides (RPs) are explained from the standpoint of the model of "regulatory cascade" consisting of stepwise induction of other RPs release (or inhibition of the release). The computerised analysis of possible physiological effects of such processes initiated by thyroliberin is compared with the long-term effects observed in experiments.

Animals↗
PubMed1989

[Comparison of the effects of thyroliberin and ACTH4-7 PGP on the learning of rats during the solving of spatial orientation tasks].

The influence of TRH (100 micrograms/kg) and ACTH4-7 Pro-Gly-Pro (15 micrograms/kg and 25 micrograms/kg) involved an acceleration of the spatial learning on the 12-arm radial maze and on T-maze in rats; an increase in the number of correct choice after short (5-10 min) retention interval; and affected the working and reference spatial memory in the test of reinforced place performance. The effects of the TRH and ACTH4-7 Pro-Gly-Pro did not interfere with one another.

Adrenocorticotropic Hormone↗
PubMed1989

[Anticonvulsive properties of peptide ACTH4-7 pro-gly-pro detected in amygdaloid kindling and audiogenic epilepsy in rats].

Effects of the ACTH4-7 pro-gly-pro, calcium valproate ("Germed", DDR) and nembutal on kindling preparation and audiogenic epilepsy were investigated. Development of after-discharges in response to repeated amygdaloid electrical stimulation was assessed in normal rats and in rats susceptible to audiogenic epilepsy (KM line of rats). ACTH4-7 pro-gly-pro had an anticonvulsant profile. ACTH4-7 pro-gly-pro decreased seizure threshold in the audiogenic epilepsy test, but did not prevent the motor convulsions.

Acoustic Stimulation↗
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↗