Publications by authors named "Figurina I"

Spectral analysis was used to study the dynamics of low-frequency hemodynamic fluctuations in male Wistar rats following 2-wk tail-suspension. The experiment was performed with intact rats and rats with the sympathetic nervous system damaged by 6-hydroxidofamine injection. Equally in intact and desympathetized animals, low-frequency fluctuations of arterial pressure (AP) were found less intensive within the 0.

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Social isolation is a stress factor increasing animal anxiety and impairing food-reinforced instrumental learning. Social isolation modulates sensitivity to psychoactive substances: it potentiated the depressive and analgesic effects of morphine, but attenuated the activating and anxiogenic effects of caffeine. These behavioral changes and changes in sensitivity to psychoactive agents can be explained by a well-known phenomenon of activation of the endogenous opioid system during stress.

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Effects of acute and chronic caffeine intake on the level and pattern of morphine self-administration behavior in WAG/G and Fisher-344 rats were studied. Both acute and chronic caffeine intake decreased morphine self-administration only in WAG/G rats, which attested to increased sensitivity of these rats to reinforcing effects of morphine. Possible relationship between the observed changes and increased anxiety in rats receiving caffeine is discussed.

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Effect of one-day and chronic (3 week) drinking of 0.1% caffeine as a single source of fluid on anxiety in rats with different anxiety level (either genetically determined or individually acquired) was studied. When housed in groups, Fisher-344 rats had a significantly higher anxiety level than WAG/G rats.

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We studied the effects of substance P on intravenous self-administration of morphine in WAG/G and Fischer-344 rats. By the end of week 2 the daily amount of self-administered morphine in WAG/G rats was higher than in Fischer-344 rats. Treatment with substance P markedly suppressed self-injection of morphine, particularly in low doses.

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The effect of circulation arrest on the development of stress-induced injuries was studied in Krushinsky-Molodkina rats genetically predisposed to audiogenic seizure. Resuscitated rats were subjected to acoustic stress 1.5 month after circulation arrest.

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In cylindric fragments of the rat tail arteries, activation of the smooth muscle with noradrenaline was found to enhance the vessels' rigidity both in stretching and in compression, i.e., the activation of the smooth muscle layer decreased the arteries' pliability.

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In 13 laboratory rats with bilateral auditory cortex ablation, the border frequency of amplitude-modulation still allowing differentiation between tonal and amplitude-modulated stimuli, did not change after bilateral section of the brachii of the posterior colliculi. Bilateral auditory cortex ablation and section of the brachii drastically disturbed this differentiation when the modulation frequencies were higher than 27-31 Hz. The data suggest that the completion of coding of amplitude-modulated stimuli does not take place at the level of the medial geniculate body, and that border frequencies defined after auditory cortex ablation are linked with the frontier posterior colliculi--thalamo-cortical system.

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Cortical projections of the medial geniculate body have been studied in dolphin Phocaena phocaena by the method of anterograde degeneration of Fink--Heimer. For this purpose, in two animals a unilateral electrocoagulation of the thalamic auditory center has been performed. The caudal part of the microcellular nucleus of the medial-geniculate body has been stated to project ipsilaterally on the parietal, parietooccipital and temporal cortex.

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