Peculiarities of painful stress after neurotensin administrations in rats with toxic damage of serotoninergic brain structures

Abstract

The purpose of this study was to elucidate the influence of neurotensin on realization of locomotor reactions of passive avoidance and painful stress after actions in rats with lesion of serotoninergic brain structures. It was shown that administration ofselective neurotoxin, 5,7 dihydroxytryptamine, into raphe dorsalis nucleus enhanced, while administration into substantianigra, on the contrary, weakened reproduction of passivedefence reactions at rats. In painful stress after action the neurotoxin administration into the specified brain formationscaused differentdirected changes of locomotor activity of ratsand its behaviour in the elevated Xmaze. Neurotensin microinjections into substantia nigra and nuclei caudatus weakenedneurotensin effects and, thus, increased adaptive character ofdefensive behaviour in rats with deficit of serotoninergic neuronfunction. Alleviation, by neurotensin, of negative influence ofpainful stress on animal behaviour can be manifestation of anx iolitic properties of this neuropeptide and specify its protectiverole in emotional stress.

Keywords

• neurotensin
• neurotoxin
• dopamine
• serotonin
• substantia nigra
• passive avoidance conditioning
• behavior