Gonadectomy attenuates turning behavior produced by electrical stimulation of the nigrostriatal dopamine system in female but not male rats.

Rotational behavior induced by electrical stimulation of ascending dopamine neurons is used as a behavioral model to investigate gender and hormonal influences on extra-hypothalamic dopamine systems. Steroid hormones influence the metabolism of many dopaminergic drugs, and therefore this approach avoids the complications inherent in drug-induced behavior models of dopamine activity. We found that gonadectomy of female, but not male, rats severely attenuates electrical stimulation-induced rotational behavior. This suggests that some female gonadal steroid hormone(s) may modulate the activity of ascending dopamine neurons, while male gonadal hormones do not.