Testosterone Replacement Attenuates Haloperidol-Induced Catalepsy in Male Rats

Purpose: Parkinson’s disease (PD) is a progressive neurodegenerative disease. Recent studies have indicated a higher prevalence of PD in male gender. Furthermore testosterone deficiency is more common among male parkinsonians in compare to healthy men. This study was aimed to investigate the effect of testosterone on catalepsy, in male rats. Methods: The study carried out on male Wistar rats. To induce catalepsy, haloperidol (1 mg/kg, i.p) as D2 antagonist was administered before testing animals via Bar test. Animals were gonadectomized to investigate testosterone elimination effect on catalepsy, and also the androgen receptor blocker, flutamide, and the aromatase inhibitor, letrozole, were administered in certain groups of animals. The bar test method was used to evaluate haloperidol-induced catalepsy. Results: Haloperidol 1 mg/kg, i.p, was able to induce catalepsy. Gonadectomy worsened the catalepsy and subchronic testosterone replacement could restore this effect to the level of normal animals. While low dose of flutamide administration represented an improvement in cataleptic symptoms, higher doses worsened catalepsy. Letrozole(4mg/kg,sc) administered animals represented nearly the same cataleptic symptoms as the control group. Conclusion: Testosterone deficiency increases catalepsy and testosterone replacement can significantly be effective in catalepsy remission. It seems that the anticataleptic effect of testosterone is exerted through affecting on androgenic receptors.