Effects of some dibenzo-azepines on suppressed and nonsuppressed behavior of squirrel monkeys

Six dibenzo-azepine derivatives were compared for their effects on suppressed and nonsuppressed behavior of squirrel monkeys. Monkeys responded by pressing a lever under a two-component fixed-ratio schedule of food presentation in which responding in one component was suppressed by response-produced electric shock. Intermediate doses (0.3-1.0 mg/kg IM) of selected unsubstituted and 8-chlorine-substituted dibenzo-azepines (perlapine, 106-094, and clozapine) increased responding that was suppressed by electric shock, whereas selected 2-chlorine-substituted dibenzo-azepines (loxapine, clothiapine, and 105-056) did not consistently increase suppressed responding at any dose (0.001-0.1 mg/kg IM). All six dibenzo-azepines decreased nonsuppressed responding in a dose-related manner, with the 2-chlorine-substituted derivatives being 16-50 times more potent than their unsubstituted or 8-chlorine-substituted congeners. These structure-activity relationships indicate that the effects of the dibenzo-azepines on both suppressed and nonsuppressed behavior differ qualitatively depending on the location of the chlorine substituent.