[Participation of hypothalamic noradrenergic structures in the reproduction of conditioned "passive" avoidance reactions].

The level of fluorescence of noradrenaline in the hypothalamic nuclei was studied with histofluorescent method during reproduction of conditioned reaction of passive avoidance (CPA) by rats of the Wistar line. Animals' "emotionality" was estimated by the number of defecation boluses. Reproduction of CPA in the first rest leads both to an increase in animals' "emotionality" and to an activation of noradrenergic terminals of the hypothalamic nuclei. After extinction of the emotional component of the conditioned reaction reproduction of CPA motor component does not lower the level of noradrenaline fluorescence in the studied structures. The obtained data permit to suggest participation of noradrenergic system in the emotional component of conditioned defensive reactions.