Effects of chronic domperidone treatment on rat conditioned avoidance behavior

The effects of chronic administration of domperidone (DOM), a peripherally acting anti-emetic and hyperprolactinemic D2-dopaminoceptor antagonist, on active and inhibitory conditioned behavior were tested on male and female rats. DOM (4 mg/kg) was injected ip daily either for 5 or 30 days. Although treatment for 5 days failed to affect experimental parameters, treatment for 30 days impaired the performance of active conditioned avoidance of female, but not male, rats. This effect was no longer observed 7 days after ending treatment. No effects of DOM treatment were observed on active conditioned avoidance of male rats or on inhibitory conditioned behavior of all rats. These data suggest that female rats are more susceptible to the hyperprolactinemic effects of DOM than male rats. However, an influence of estrous cycle interruption cannot be rejected.