CIRCADIAN PHASE-SHIFTS INDUCED BY CHLORDIAZEPOXIDE WITHOUT INCREASED LOCOMOTOR-ACTIVITY

Phase advances of circadian locomotor rhythms in response to the benzo diazepine triazolam (TRZ) administered at circadian time 6 appear to b e mediated by locomotor activity. The possibility that increased activ ity also mediates shifts induced by the benzodiazepine chlordiazepoxid e (CDZ) was investigated. Hamsters injected with CDZ 7 h before dark o nset exhibited phase advances despite being confined to their nest box es for 3 h after receiving the drug. These shifts did not differ signi ficantly from advances seen in hamsters which were allowed access to t he rest of the cage after injections. In other experiments, the behavi oral effects of both CDZ and TRZ were examined during the 5 h after in jection. There was significantly more motor activity observed after in jection of TRZ than CDZ. These results suggest that phase-shifting eff ects of some benzodiazepines can occur without inducing activity.