Anxiolytic-like Effect of Testosterone in Male Rats: GABAC Receptors Are Not Involved

OBJECTIVES The effect of testosterone on anxiety-like behaviors has been the subject of some studies. There is evidence that testosterone modulates anxiety via GABA (gama aminobutyric acid) and GABAergic system. The involvement of GABAC receptors in those effects of testosterone on anxiety-like behaviors of the rats was investigated in the present study. MATERIALS AND METHODS A group of rats received subcutaneous injections of testosterone (5, 10 and 20 mg/kg). Two groups of rats received intracerebroventricular injections of either CACA (GABAC agonist, 0.125 μg/rat) or TPMPA (GABAC antagonist, 3 microg/rat) following administration of testosterone (5, 10 and 20 mg/kg). After the injections, the rats were submitted to the elevated plus-maze test of anxiety. RESULTS The rats received testosterone alone, showed a decreased in anxiety-like behaviors (P< 0.01). Administration of either CACA or TPMPA did not modify animals' behavior compared to the rats received testosterone alone. CONCLUSION The results of the present study showed that administration of testosterone induces anxiolytic-like behaviors in the rats and GABAC receptors possibly are not involved in the anxiolytic effect of testosterone.