To investigate the involvement of oxytocin in their short-term lasting
olfactory memory performance, adult female Wistar rats (n = 12) were
tested for their juvenile discrimination abilities. As measured by the
ir exploratory behavior towards juveniles, the adult rats were able to
discriminate between a previously exposed juvenile and a novel one as
long as the interval between the two exposures was less than 180 min.
This ability was maintained across all days of the estrous cycle and
was unaffected by intracerebroventricular administration of synthetic
oxytocin (1 ng/5 mu l Ringer's solution) or Ringer's solution immediat
ely after the first exposure. However, treatment with the oxytocin rec
eptor antagonist des-Gly-NH2 d(CH2)(5)[Tyr(Me)(2)Thr(4)]OVT interfered
with the ability to establish this kind of olfactory memory although
the vasopressin V1 receptor antagonist d(CH2)(5)Tyr(Me)AVP (100 ng/5 m
u l each) via the same route did not. This suggests that within a narr
ow range of concentrations endogenous oxytocin, but not vasopressin, i
s critically involved in short-term olfactory memory for juvenile cons
pecifics in female rats. These data are discussed in the light of sexu
al dimorphic brain development. (C) 1998 Elsevier Science B.V.