Post-parturition and late lactation urine: long-term effects of exposure on mouse activity and sniffing behaviour

From the time of separation from their mothers infant mice were exposed for 10 consecutive days to urine from post-parturitional and late-lactational donor mice. They were then tested when adult on activity and sniffing behaviour. The sample of mice exposed to urine from late-lactational donors was associated with reduced activity when compared with mice exposed to post-parturitional urine and a water control sample. The long term effects of the urine on behaviour were also apparent in positional preferences in an open arena as judged by frequency of entry, and to a lesser extent, the time spent in the left and right hand segments. Mice exposed to late-lactational urine sniffed less than the other treatment samples though preferences for sniffing the urine that they had been exposed to in infancy were less marked. The urine did not accelerate puberty, but mice in the control sample had more vaginal dioestrous smears and fewer smears with a predominance of epithelial cells.