INTERFERING WITH SOMATOSENSORY STIMULATION FROM PUPS SENSITIZES EXPERIENCED, POSTPARTUM RAT MOTHERS TO OXYTOCIN ANTAGONIST INHIBITION OF MATERNAL-BEHAVIOR

Proximal separation (PS) refers to isolating pups in small cages so da rns can hear, smell, and see pups but have very limited physical conta ct with them. Six days of PS diminished the number of discernible oxyt ocin-(OT) immunostaining perikarya in forebrain areas of rat dams comp ared with 6 days of total separation (TS) or no separation (NS) from p ups. Dams exhibited a more rapid resurgence of maternal behavior after 4-6 days of PS than after 4-6 days of TS. Bilateral infusion of the O T antagonist (OTA; 1 mu g/mu l/side) into the ventral tegmental area b locked the resurgence of maternal behavior after 3-6 days of PS but no t after 2 days of PS or 4-6 days of NS. The conclusion was that PS for 3 or more days reinstates OT as necessary and sufficient for the acti vation of maternal behavior in experienced rat mothers. These findings suggest that some aspects of somatosensory stimulation from pups regu late the role of OT in the control of maternal behavior.