MOTIVATIONAL PROPERTIES OF OXYTOCIN IN THE CONDITIONED PLACE PREFERENCE PARADIGM

We hypothesized that oxytocin might have intrinsic reinforcing propert ies and studied it using a conditioned place preference. Three studies examining motivational properties of oxytocin in nonpreferred, prefer red, and balance designs were performed utilizing two compartment appa ratus. On alternate days, compartments were paired with subcutaneously injected oxytocin (6 mg/kg) or saline, and animal pre-and post-condit ioning place preference was compared. Whereas in animals paired with s aline there was a shift to a lack of preference, oxytocin-treated anim als reversed their preference, spending more time in a previously unpr eferred, compartment. In preferred compartment design, oxytocin-treate d animals further increased their preference, whereas saline-treated a nimals decreased their preference toward a nonpreference for either co mpartment. Our results demonstrate that oxytocin produces a reliable a nd robust preference for the environment with which it is repeatedly a ssociated, and has rewarding or potentially anti-aversive properties. Future studies are needed to distinguish among these possibilities. (C ) 1997 American College of Neuropsychopharmacology. Published by Elsev ier Science Inc.