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Biomedical subjects

G K Krivobok

Publications and source records attributed to G K Krivobok.

At least 19 recordsLinked to original sources
PubMed2006

Neurochemical mechanisms of the dorsal pallidum in the antiaversive effects of anxiolytics in various models of anxiety.

In conditions in which rats had a free choice between dark and light chambers, microinjections of glutamic acid, serotonin, and campiron into the globus pallidus showed that these agents have antiaversive properties in a threatening situation test but not in an illuminated area test. Dopamine, apomorphine, GABA, chlordiazepoxide, phenibut, and indoter injected locally into this formation of the basal ganglia had no effect on the mechanisms of voluntary movement but counteracted anxiety states in both behavioral models. These results provide evidence that the monoaminergic and aminoacidergic systems of the dorsal pallidum have different functional roles in the operative regulation of behavior for aversive stimuli of different modalities. Prior intraperitoneal administration of functional antagonists of these synaptotropic substances and subsequent microinjection of transmitter monoamines and amino acids and their agonists into the globus pallidus demonstrated the selective involvement of the neurotransmitter systems of the dorsal pallidum in the antiaversive effects of anxiosedative and anxioselective substances.

Animals↗
PubMed2005

[Neurochemical mechanisms of dorsal pallidum in antiadverse effects of anxiolytics of different models of anxiety].

Microinjections of glutamine acid, serotonine and campiron into globus pallidus reveal antiadverse properties of ratsin in the test with avoiding "threatening situation" but not with "illuminated site" under the conditions of rats' free choice between light and dark sites. Dopamine, apomorphine, GABA, chlordiazepoxide, phenibut and indoter injected locally into this formation of basal ganglia do not affect the mechanisms of the involuntary movement, but counteract the conditions of anxiety in both models of behaviour. These results show different functional role of monoamino- and aminoacidergic systems of dorsal pallidum in operative regulation of behaviour with changing of aversive stimulus modality. Preliminary intraperitoneal injection of functional antagonists of investigated synoptotropic followed by microinjection of monoamines and amino acids into globus pallidus reveal selective involvement of neuromediator systems of dorsal pallidum into antiadverse anxiosedative and anxioselective actions.

Animals↗
PubMed2001

The role of neurochemical mechanisms of ventromedial hypothalamus in various models of anxiety in rats.

Microinjections of glutamic acid, serotonin, and sulpiride in the ventromedial hypothalamus reduced anxiety in an illuminated platform avoidance task in rats, while dopamine, apomorphine, picrotoxin, and memantine increased it. Similar injections of phenylephrine and yohimbine reduced anxiety in threatening situation task only, while GABA reduced it in both tasks. It is suggested that various emotional and stress phenotypes are realized through functionally different neurochemical mechanisms of ventromedial hypothalamus.

Adrenergic Agents↗
PubMed1993

[The role of monoamin- and acidergic mechanisms of the hippocampus in anxiety states of different origins and their participation in the antiaversive effects of anxiolytics].

The experiments on rats with tests of avoiding "lighting square" and "threatening situation" and with the chemical stimulation of dorsal and ventral hippocampus with dopamine, 5-HT, GABA and glutamine acid, showed different functional significance of these monoamines and acidergic transmitters agents in the states of anxiety of heteromodal aversive genesis. It seems that the variations in the action spectrum of anxiolytics under study are due to unequal degree of 5-HT and GABA-ergic transmitter mechanisms of dorsal and ventral hippocampus.

Animals↗
PubMed1992

[The mediator mechanisms of the ventral hippocampus in anxiety states formed by different aversive exposures].

Microinjections of monoamines and amino acids into rat ventral hippocampus showed functional relevance of GABA- or dopamine- and 5-HT-ergic mechanisms of this structure of brain formed by aversive actions of diverse biological importance rather than glutamate-ergic ones. The participation of hippocampus monoamine- and acidergic mechanisms in the origin of diverse aversive anxiety is discussed.

Animals↗
PubMed1975

[Adrenoreception characteristics of the neurons of the superior cervical and caudal mesenteric sympathetic ganglia of the cat].

Experiments were conducted on the supeior cervical and the caudal mesenteric sympathetic ganglia of a cat; it was shown that dophamine (DA), similarly to noradrenaline (NA) and adrenaline (A), depressed the cholinergic conduction. The activity of DA in the superior sympathetic ganglion was less than that of the NA and A 2- and 3-fold, respectively, and in the caudal mesenteric ganglia DA was 50 times more active than NA by the capacity to depress the cholinergic conduction. The effects of DA and NA in the superior cervical ganglia were eliminated by dyhydroergotamine, phentholamine and haloperidol, but not by tropaphen and chlorpormazine. In the caudal mesenteric ganglia the inhibitory effect of NA was decreased by phentholamine, dihydroergotamine and chlorpromazine, but not by haloperidol. On the contrary, haloperidol and chlorpromzine decreased the depressive effect of DA on the cholinergic conduction in the caudal mesenteric ganglion, whereas phentholamine, dihydroergotamine and deseryl proved to be ineffective. It is supposed that the manifestation of the dopaminergic mechanism of inhibition of cholinergic conduction in the caudal mesenteric sympathetic ganglion could underlie the dilatation of the mesenterial and renal vessels and its hypotensive action caused by DA.

Action Potentials↗
PubMedDate not supplied

[Monoaminergic influences of the caudate nucleus on conditioned food-getting reactions in rats].

Influence of microinjections of monoamines and glutamic acid into the caudate nucleus head on conditioned food-procuring reaction was studied in experiments on rats. Dopamine, noradrenaline and glutamic acid prolong the latency of the reflex, while serotonin reduces it. However, all the drugs tested reduce the number of conditioned food-procuring movements. The effects of dopamine are achieved through neurone receptors of the caudate nucleus which are sensitive to haloperidol and chlorpromazine; effects of serotonin are mediated through the D-serotoninoreactive systems, and those of noradrenaline, through the alpha-adrenoreactive systems of the neostriatum neurones. The inhibitory effect of glutamic acid is not due to the action on the serotonino-, adreno-, or dopamine receptors of caudate units.

Animals↗
PubMedDate not supplied

[Neurochemical mechanisms of the inhibitory influence of the hippocampus on the conditioned food-getting reaction in rats].

A study was made of the influence of microinjections of dopamine, noradrenaline, serotonin and glutamic acid into the dorsal hippocampus on the food-procuring conditioned reaction of rats. All the examined drugs lengthen the latency of the conditioned alimentary reaction. However, the number of pushes of the door leading to the feeding through and the magnitude of the reflex are increased by catecholamines and glutamic acid, but reduced by serotonin. The dopamine effects are achieved through archicortex neurones receptors, sensitive to haloperidol, the noradrenaline effects, through alpha-adrenoreactive, and of serotonin, through M-serotoninsensitive structures of the hippocampal neuronal systems. The modulating influence of glutamic acid on the food-procuring conditioned reaction is not connected with the active on dopamine-, adreno or serotonin neuronal receptors of the rat dorsal hippocampus.

Animals↗
PubMedDate not supplied

[Dopamine receptors of the smooth muscles].

It is shown that the interuption of sympathetic nerves in the smooth muscles of the deferent duct or ejejunum of rats achieved by a 4-day keeping of the duct in cold or by the reserpine treatment of the animals does not produce any essential effect on the dopamine action. The contraction of smooth muscles in the isolated deferent duct, mesenteric and renal vessels of rats is effectively eliminated by alpha-andrenolytics (dihydroergotoxin, phentolamine), while the inhibitory effects of dopamine (lowering of vasotonicity of the rats' jejunum tone) are suppressed with propranolol. Galoperidol and methylergometrin display in experiments with smooth muscle organs but a low degree of antagonism to dopamine. The activity of phentolamine as an antagonist of norepinephrine and dopamine in the deferent duct is identical.

Animals↗
PubMedDate not supplied

[Differences in hypothalamic monoaminergic mechanisms in heterogeneous conditioned reflexes in rats].

Monoamines and aminoacids were microinjected in the middle medial hypothalamus of rats following the elaboration of conditioned food-procuring or avoidance reflexes. The glutamine acid had no effect on the avoidance reflex (AR), but stimulated the motor activity and the food-procuring reflex (FR), shortening its latencies, increasing the number of the conditioned food-procuring movements and the reflex size. Dopamine decreased the motor activity, but did not influence the AR latencies, whereas norepinephrine prolonged the AR latencies without changing the motor activity. Both catecholamines, while having no effect on the muscle tone, suppressed FR, prolonging the latencies and decreasing the reflex and the number of conditioned food-procuring movements. Local administration into the hypothalamus of GABA prolonged the latencies of heteromodal conditioned reflexes, whereas the serotonin had no effect on the recorded FR parameters, but facilitated AR significantly reducing its latencies.

Animals↗