Olfactory basis for the delayed onset of maternal behavior in virgin female rats: Experimental effects.

A previous study showed that intranasal zinc sulfate (ZnSO4) treatment shortens the latencies for the onset of maternal behavior in nonpregnant rats. The present study attempted to determine whether after recovery from the effects of ZnSO4 treatment, the latencies for maternal behavior increased. In Exp I, with 28 Charles River female rats, nonpregnant Ss were intranasally infused with ZnSO4 or air were left untreated and exposed to pups starting 48 hr later. Olfactory discrimination tests using chocolate bits were done simultaneously. The ZnSO4 treatment resulted in short latency maternal behavior (1.1 days) compared with latencies of control Ss (3.8 days), but neither group showed any loss of olfactory discrimination. 3 wks later, ZnSO4-treated Ss showed increased latencies for all but retrieving, while control groups showed decreased latencies for all maternal behaviors. In Exp II, with 13 nulliparous Charles River females, intranasal ZnSO4- and air-treated Ss were given olfactory discrimination tests under food deprivation, using chocolate bits and guinea pig pellets. Choice of guinea pig pellets was more severely affected than choice of chocolate bits, but recovery of the discriminations was complete in 4-5 days. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)