“…Administration of AVP induces a dose-dependent long lasting inhibition of extinction of active avoidance behavior and an improvement of passive avoidance behavior (Van Wimersma Greidanus and De Wied, 1977). Concerning endogenous AVP it has been shown that Brattleboro rats, homozygous for diabetes insipidus, which lack AVP completely, show disturbances in avoidance behavior (De Wied, Bohus, and Van Wimersma Greidanus, 1975;Bohus, Van Wimersma Greidanus, and De Wied, 1976;Bailey and Weiss, 1979) and similar phenomena are observed in Wistar rats treated intracere-broventricularly (i.c.v.) with AVP-antibodies in order to neutralize bioavailable AVP in the brain (Van Wimersma Greidanus, Dogterom, and De Wied, 1975;De Wied, 1975a, Bohus, Urban, Van Wimersma Greidanus, and.…”