The effect of midazolam and ?-carboline carboxylic acid ethyl ester on behaviour, steroid hormones and central monoamine metabolites in social groups of talapoin monkeys

Abstract

Established social groups of talapoin monkeys show rank-related differences in aggressive, social and sexual behaviours and visual monitoring, as well as in endocrine and monoamine profiles. Here we describe the effects on these variables of an “anxiogenic drug”, β-carboline carboxylic acid ethyl ester (β-CCE), and an anxiolytic drug (midazolam) given to either dominant or subordinate male talapoins. In dominant animals β-CCE increased aggression and visual monitoring but reduced sexual behaviour. Treatment of subordinate animals with β-CCE served only to increase visual monitoring. Conversely, treatment with a non-sedative acute dose of midazolam in dominants reduced aggressive behaviour and increased sexual behaviour, whereas in subordinates no behavioural changes were noted. Significant effects on endocrine and neurochemical variables were not seen with the acute drug treatments employed. Nevertheless, the results show that drugs which modulate anxiety produce status-dependent behavioural effects.