THE EFFECTS OF INFUSION OF ARGININE-VASOPRESSIN, OXYTOCIN, OR THEIR ANTAGONISTS INTO THE OLFACTORY-BULB UPON SOCIAL RECOGNITION RESPONSES IN MALE RATS

In the present report, the peptides arginine vasopressin (AVP), oxytoc in (OXT) or their respective antagonists were infused bilaterally into the olfactory bulb to assess their effects upon recognition responses . Recognition responses were determined in a social discrimination par adigm and consisted of measuring the amount of investigation directed to either the same (previously exposed) or novel juvenile rats under c onditions in which clear recognition responses are either present as t ested with a 30 min inter-exposure interval or absent as tested with a 120 min inter-exposure interval. Infusion of AVP or OXT resulted in p reserved recognition responses, as tested with a 120 min inter-exposur e interval, compared with that observed in vehicle-infused controls. W hen animals were infused with the AVP or OXT antagonists using two dif ferent doses and tested for the display of recognition as tested with the 30 min inter-exposure interval, no effects of these antagonists we re obtained with either dose. These results demonstrate that the olfac tory bulb represents an additional important central nervous system ta rget site where these peptides can act to preserve social recognition responses. Moreover, our results suggest that the underlying mechanism s by which these peptides function within the olfactory bulb differ as a function of whether they are involved with the display versus prese rvation of recognition responses. (C) 1998 Elsevier Science Inc.