Exploratory and socio-sexual behaviour in the male laboratory rat: a methodological approach for the investigation of drug action.

There is an increasing demand for appropriate methods for analysing the pharmacological and toxicological action of chemical agents on behavioural patterns. The present study describes a non-instrumental approach to the study of exploratory and socio-sexual behaviours in the laboratory male rat. The behaviours were differentiated in terms of latency of onset, incidence, frequency and duration. Castrated and intact males were tested under three defined test situations. One test was focused on exploratory behaviour and two tests in which the male encountered an oestrous female or a castrated male were set up to study social and sexual behaviours. A multivariate statistical method was used to analyse differences in the behavioural profiles observed in the different tests. The data show that simultaneous recording of several spontaneous behaviours may be a useful technique for investigating how a compound influences behavioural processes.