Effects of chlordiazepoxide and beta-carboline 3-carboxylic acid ethyl ester on non-suppressed and minimally-suppressed responding in the squirrel monkey.

Author(s): Glowa JR, Insel TR

Affiliation(s): Biopsychology Unit, NIMH, Bethesda, MD 20892.

Publication date & source: 1992, Life Sci., 50(1):7-14.

Publication type:

Lever-pressing of squirrel monkeys was maintained under a multiple fixed-interval (FI) 5-min schedule of food presentation. In one component, responding was suppressed to various degrees by the presentation of electric shock following each 30th response. When responding was either substantially or minimally suppressed, intermediate doses of chlordiazepoxide (CDAP, 1-30 mg/kg) increased both suppressed and non-suppressed responding. Beta-carboline 3-carboxylic acid ethyl ester (beta-CCE, 0.1-3 mg/kg) had little effect at low to intermediate doses (0.1-0.3 mg/kg) and decreased both minimally-suppressed and non-suppressed responding to a comparable extent at higher doses. Repeated daily dosing with beta-CCE (up to 10 mg/kg) resulted in rapid tolerance to its rate-decreasing effects. As agonists do not typically exhibit rapid tolerance for anxiolytic efficacy, the current results suggest that some behavioral effects of inverse agonists may not be strictly opposite those of benzodiazepines.