[The pharmacologic analysis of modulated substance P induced by stimulation of the lateral hypothalamus]. / Farmakologicheskii analiz modulirovannogo substantsiei P povedeniia, vyzvannogo stimuliatsiei lateralnogo gipotalamusa.

The present investigation was undertaken to examine the neurochemical mechanisms of the modulatory effect of substance P (SP) on feeding behavior induced by threshold electrical stimulation of the lateral hypothalamus (LH) in rabbits. The administration of SP, 15 nmol, was found to transform feeding induced by stimulation of LH into escape. The phenomenon was shown to begin at min 20, and to last up to min 60 after SP injection. In the experiments, some antagonists of classic neurotransmitters were injected into the marginal vein of the rabbit ear. An important role of catecholaminergic and M-cholinergic formations in the brain in the SP transformation of their feeding behavior into escape was found in electric stimulation of LH. H-cholinergic and GABA-ergic antagonists produced no effect on the modulatory effect of SP.

[A pharmacological analysis of pentagastrin-modulated behavior evoked by stimulation of the ventromedial hypothalamus]. / Farmakologicheskii analiz modulirovannogo pentagastrinom povedeniia, vyzvannogo stimuliatsiei ventromedial'nogo gipotalamusa.

The purpose of the present investigations was to examine the neurochemical mechanisms of modulatory effect of pentagastrin (PG) on escape reaction elicited by the threshold electrical stimulation of the ventromedial hypothalamus (VMH) in rabbits. PG administration (35 mcg/kg intraventricularly) was found to transform escape into feeding. This phenomenon was shown to begin at 20 min and to last to 150 min after PG injection. The animals were treated with various antagonists to some classic neurotransmitters of the central nervous system. Kalipsol (0.25, 0.5 mg/kg intravenously) and ketanserin (0.1 mg/kg intravenously) were found to restore feeding into escape. GABA-ergic antagonist baclofen (0.25, 0.5 mg/kg) was demonstrated to shorten to about 30 min the time of feeding after PG administration. Both inderal-beta-adreno-blocker (0.25, 0.5, 1.0 mg/kg) and M-choline antagonist atropine (0.25, 0.5 mg/kg) were found to be ineffective in escape restoration in response to VMH stimulation. The experimental results suggest the important role of N-cholinergic and serotoninergic brain structures in PG transformation of escape elicited from the VMH into feeding.

[A neurochemical analysis of the substance P-induced reordering of the feeding behavior evoked by electrical stimulation of the lateral hypothalamus]. / Neirokhimicheskii analiz perestroiki veshchestvom P pishchevogo povedeniia, vyzvannogo élektricheskim razdrazheniem lateral'nogo gipotalamusa.

The substance P when administered intracerebroventricularly (15 nmol) led to a transformation of feeding elicited by threshold electrical stimulation of the lateral hypothalamus into an escape reaction in rabbits. Obsidan, Inderal (0.25 and 0.5 mg) and droperidol (0.3 mg) injected intravenously were found to restore the functional properties of the hypothalamic feeding centre. No changes in the escape reaction were observed after kalipsol (ketaminum) administration. The data obtained suggest the important role of the catecholaminergic brain structures in the mechanisms of the transformation of the functional properties of the hypothalamic feeding centre under the influence of the substance P.

[Beta-adrenoblockers in the reorganizing of the food center of the hypothalamus under the influence of substance P]. / Beta-adrenoblokatory v perestroike pishchevogo tsentra gipotalamusa pod vliianiem veshchestva P.

An ability of substance P (15 nmol intracerebroventricularly) to transform functional properties of the hypothalamic feeding center manifested in escape reaction in response to threshold electrical stimulation of this motivation center in rabbits. Beta-adrenergic antagonists inderal and obsidan (0.25, 0.5 mg, respectively) injected intravenously were found to restore feeding elicited by electrostimulation of the hypothalamic feeding center. However, escape reaction, elicited from the feeding center under substance P was found unchanged after intravenous administration of 0.25 mg kalipsol. The data obtained suggested an important role of beta-adrenergic mechanisms in substance P transformation of the functional properties of the hypothalamic feeding centre.

[Role of substance P in regulating the feeding behavior and the avoidance reaction in the rabbit]. / Rol' veshchestva P v reguliatsii i pishchevogo povedeniia i reaktsii izbeganiia u krolikov.

Similar changes in feeding and avoidance reaction in spite of the way of substance P administration (30 mgk/kg intravenously or 14,8 nmol intraventricular) were found in rabbits with electrodes implanted in various limbic-midbrain structures. Feeding was found to be more sensitive to substance P administration, as it was shown by the decrease of excitability of the hypothalamic "feeding center" and abolishing of the inhibitory and facilitatory effects on this center from the dorsal hippocampus and the midbrain reticular formation, correspondingly. New cortical-subcortical integration under substance P was presented in new characteristics of EEG activity in neocortical areas, both background and in response to stimulation of various limbic-midbrain structures. Biochemical data let to suggest that at the neural level substance P led to destabilization of membrane structures in endoplasmatic reticulum and to redistribution of membrane-connected N-acetylneuramine acid which was directly involved in neurotransmission.

[Responses of neurons of the frontal area of the cortex of the rabbit to electric stimulation of certain limbic-mesencephalic structures after administration of substance P]. / Reaktsii neironov lobnoi oblasti kory mozga krolika na élektricheskuiu stimuliatsiiu nekotorykh limbiko-mezentsefalicheskikh obrazovanii pri vvedenii veshchestva P.

In rabbits tested on behavioural reactions by electrical stimulation of certain limbic-midbrain structures, intravenous injection of substance P (30 mcg/kg) led after 10 min of silent period to a decrease of spontaneous neuronal activity in the frontal cortex. Convergence of excitations arising from the lateral hypothalamus, the dorsal hippocampus and the midbrain reticular formation was also found to decrease after the substance P injection. Analysis of neuronal responses allowed to establish that substance P markedly changed the ascending excitations of the lateral hypothalamus and was less effective for the influences from the midbrain reticular formation.

[Substance P in the central mechanisms of the escape reaction]. / Veshchestvo P v tsentral'nykh mekhanizmakh reaktsii izbeganiia.

The role of substance P in the central mechanisms of escape reaction elicited by electrical stimulation of the ventromedial hypothalamus was investigated in chronic experiments on rabbits. Intravenous injection of substance P (30 micrograms/kg) led to a short-term (less than 10 min) increase in the threshold of stimulation of the ventromedial hypothalamus and to more stable (up to 1.5 h) disorders of the hippocampal-hypothalamic relations. After substance P injection the inhibitory effects of the dorsal hippocampus but not the facilitating influences of the midbrain reticular formation on excitability of the hypothalamic motivation center were found to be lacking. Disorders of the central mechanisms of escape reaction after substance P injection correlated with new patterns of the main EEG rhythms in different areas of the brain cortex in response to the ascending excitations of the limbic-midbrain structures. Interpreting the mechanisms of substance P involvement in escape reaction the authors point to the ability of the given peptide to interact with different transmitter systems of the brain and opiate receptors and to alter the brain blood circulation.

[Substance P in the central mechanism of the rabbit feeding response evoked by stimulation of the lateral hypothalamus]. / Veshchestvo P v tsentral'nykh mekhanizmakh pishchevoi reaktsii krolikov, vyzvannoi stimuliatsiei lateral'nogo gipotalamusa.

The effects of substance P on the central mechanisms of food motivation elicited by electrical stimulation of the lateral hypothalamus were studied in chronic experiments on rabbits. Intravenous injection of substance P (30 micrograms/kg) brought about a dramatic reduction in the excitability of the "food center" in the hypothalamus, which returned to normal 45-60 minutes after injection. Higher concentrations of substance P provoked food behavior inversion up to the replacement of food motivation by avoidance behavior. Intravenous injections of substance P disturbed the relationships between the hippocamp, midbrain reticular formation and hypothalamus seen in health. This manifested in complete cessation of the inhibitory effects of the dorsal hippocamp and facilitating influences of the midbrain reticular formation on the excitability of the hypothalamic "food center". It is assumed that disorders of the central mechanisms of food motivation may arise from the effects produced by substance P directly on the central nervous system or on the brain via changes in the hormonal balance and responses of the autonomous nervous system.