Different effects of 3-chlorophenylpiperazine on locomotor activity and acquisition of conditioned avoidance response in different strains of mice.

Mice of C57BL/6 (C57), Balb/c (BALB), and CD-1 (CD) strains were injected with 3-chlorophenylpiperazine (CPP), 1-10 mg/kg ip, and their exploratory and basal locomotor activities and acquisition of conditioned avoidance response in a shuttle-box were tested. In C57 mice CPP did not affect either locomotor activity or shuttle-box performance. In BALB mice CPP inhibited both basal and exploratory activities (the latter only in higher doses) and facilitated the acquisition of conditioned avoidance response. In CD mice CPP did not affect exploration, but inhibited basal locomotor activity and facilitated the shuttle-box performance. It is concluded that there exist large interstrain differences in responsiveness of mice to CPP, and that the drug may facilitate acquisition of conditioned avoidance response through a strain-specific, serotonin-independent mechanism.