Sex differences in escape-avoidance behaviour in BALB/c mice after haloperidol administration

Sex differences in the disruptive effects of haloperidol on escape-avoidance behaviour in OF1 mice have previously been found in several experiments in our laboratory, males being more affected than females. In the present study, we evaluated sex differences in the conditioned avoidance response of BALB/c mice in a unique training session after acute administration of haloperidol (0.25 mg kg(-1) i.p.). The number of avoidances, escapes, non-responses, crossings during the adaptation period, crossings during intertrial intervals and latencies of responses were analysed. There were statistically significant sex differences in the number of escapes and non-responses shown by the control animals treated with saline; males had more escapes and less non-responses than females. The sex differences disappeared because of the disruptive effect of haloperidol, indicating a greater inhibitory effect of the drug in males than in females. These differences in the effects of haloperidol on the escape-avoidance response in BALB/c mice indicate the generality of the phenomenon.