[Dependence of the reversal training of rats in a Y-maze and their haloperidol sensitivity on the estrous cycle phase].

In female rats estrous cycle related variations were found in reversal learning in a Y-maze. Low intersession fluctuations of errors and a high number of well relearning rats were obtained on the day of diestrus I as compared with estrus. The improvement of avoidance behaviour by haloperidol (0.1 mg/kg) also was better in diestrus I. The estrous cycle dependent variations of the behavior and neuroleptic effect may be a result of periodicity of ovarial hormones secretion and their influences on the brain dopaminergic systems.