Dependence to morphine in differentially housed rats.

Although the effects of differential housing, particularly isolation, on the action of several classes of pharmacological agents have been studied, little attention has been given to this factor in regard to narcotics. The present study involves the effects of long-term social isolation on dependence to morphine produced by pellet implants in rats. When abstinence was precipitated with naloxone, isolated rats demonstrated less jumping and less diarrhea then grouped rats. No differences were found in other signs. In addition, the differences were seen both in isolates developing muricidal behavior and those not developing this behavioral pattern.