Abstract
Behavioral effects of Diazepam (DZP), Chlordiazepoxide (CDP), Oxazolam (OXZ), Cloxazolam (CLX) and Lorazepam (LRZ) were tested in Sprague Dawley rats. These benzodiazepines showed temporal decrement in spontaneous motor activity. In the experiments on Sidman avoidance, 0.25 mg/kg, i.p. of LRZ, 2 mg/kg, s.c. of DZP, 8 mg/kg, i.p. CLX and 32 mg/kg, i.p. of CDP revealed significantly decreased response rates while 256 mg/kg, i.p. of OXZ did not. In the experiments on DRL schedule, the effective doses for decrement of response rate were 0.5 mg/kg, i.p. in LRZ, 4 or 8 mg /kg, s.c. in DZP, 4 mg/kg, i.p. in CLX, 16 mg/kg, i.p. in CDP and 32 mg/kg, i.p. in OXZ. In DZP and CDP, the significant increment of the standard deviation of inter-response time or the decrement of total number of reinforcements were found at doses in which no significant change in response rate were observed. In the experiment on CER schedule, OXZ, CLX and LRZ showed slight DZP-like CER inhibition.
