Effect of varying the duration of pre-test cage habituation on oxytocin induction of short-latency maternal behavior.

Intracerebroventricular (ICV) infusion of the peptide hormone oxytocin has been previously reported to induce the performance of short-latency maternal behavior (less than one hour of exposure to foster pups required) in estrogen-treated, ovariectomized virgin rats. Tests for the effect of ICV oxytocin in maternal behavior latency have included transfer of animals from their home cage to a larger test cage one to two hours before oxytocin infusion. The importance of this test feature on peptide-induced short-latency maternal behavior was evaluated by varying the duration of the pre-test cage habituation. The responses of ovariectomized, estrogen-primed Zivic-Miller Sprague-Dawley rats housed in the test cages one week, two hours, or 0 hours before oxytocin or saline infusion were compared. It was found that only the rats given two hours of pre-test cage habituation responded to ICV oxytocin treatment with short-latency maternal behavior. This result is discussed with regard to the failure of other investigators to elicit short-latency maternal behavior with oxytocin. Possible neuroendocrine mechanisms for the interaction of degree of environment novelty with oxytocin-induced behavior are considered.