Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons and is more prevalent in men over 60 years. In postmenopausal women, PD often progresses more aggressively, which may be related to the abrupt decline in sex hormones. We investigated the progression of reserpine-induced parkinsonism (RES) in middle-age ovariectomized (OV) rats. Female Wistar rats (n=32, 8 months old) with regular estrous cycles were used. Sixteen animals underwent bilateral ovariectomy, and one month after surgery, the absence of estrous cycles was confirmed by vaginal cytology. Animals were allocated to four groups: intact female (CTL-vehicle), intact females with RES (RES), ovariectomized females (OV-vehicle), and ovariectomized females with RES (OV-RES). Parkinsonism was induced with RES (0.1 mg/kg, s.c., every 48 h for 40 days. Behavioral tests included catalepsy, open field and oral movements (OM) (CEUA: 6628240125). Ovariectomized anticipated and worsened RES-induced motor deficit in catalepsy from the day 24th onward but did not exacerbate locomotor impairment in the open field. In the MO test, increases in vacuous chewing, tongue protrusion and oral tremor induced by RES were not intensified by ovariectomy. In conclusion, our findings suggest that female sex hormones deficiency accelerates catalepsy motor deficit but does not affect other motor impairments in the reserpine parkinsonism model.
Keywords: Parkinsonian disorders; Sex hormones; menopause; reserpine.