Humoral factors underlying maternal behavior at parturition: Cross transfusion between freely moving rats.

Used 64 female Charles River CD rats to develop a new method for cross-transfusing blood between freely active rats in order to study humoral factors involved in the induction of maternal behavior. Chronically implanted heart catheters mounted on the S's neck were attached to flow-through swivels and a peristaltic pump to shunt blood between Ss. Blood was cross-transfused for 6 hr. between pairs of virgins and between mothers and virgins, beginning at 24 hr. before parturition, 30 min. after parturition, and 24 hr. after parturition. Pups remained with the virgins from the beginning of the transfusion. Only blood from newly parturient mothers induced maternal behavior (all components except nest building in a significant proportion of virgins; prepartum blood was slightly more effective than blood transfused 24 hr. after parturition. Cross-transfusion resulted in the shortest mean latency for the appearance of maternal behavior (e.g., retrieving) found thus far (14.5 hr.). (38 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)