[The effect of bradykinin, vasopressin and ACTH (4-10) on the morphine withdrawal syndrome in morphine-dependent rats of 2 inbred strains].

: The effect of intranasal administration of bradykinin, ACTH(4-10) fragment, and vasopressin on the withdrawal syndrome was studied in morphine-dependent rats of two inbred strains, WAG/G and Fischer-344. Morphine dependence was stronger and the withdrawal syndrome had a more severe course in WAG/G rats. Intranasal administration of bradykinin and the ACTH(4-10) fragment in the dose used had no effect on the expression of the withdrawal syndrome in rats of both strains. Intranasal administration of vasopressin intensified the withdrawal syndrome in Fischer-344 rats but not in WAG-G rats. It may thus be supposed that the genetic differences in the level of endogenous vasopressin or the sensitivity of its receptors are related to the resistance to morphine dependence formation. These data, however, are of a preliminary character and study of their mechanisms will be the purpose of further research.