Blockade of 5-HT1A receptors reverses anxiety-like behavior in gonadectomized male rats

The aim of the present study was to explore the effects of 8-OH-DPAT, 5-HT1A receptor agonist and NAN-190, 5-HT1A receptor antagonist on anxiety-related behavior in the adult gonadectomized (GDX) male rats. Moreover, another goal of this work was to investigate whether the combination of 8-OH-DPAT or NAN-190 plus testosterone propionate (TP) could affect anxiety-like behavior more than TP alone in the adult GDX rats. Two weeks after gonadectomy, GDX rats were subjected by treatments with the solvent, TP (0.5 mg/kg, s.c.), 8-OH-DPAT (0.05 mg/kg, s.c.), NAN-190 (0.1 mg/ kg, i.p.), 8-OH-DPAT in a combination with TP or NAN-190 in a combination with TP during 14 days. Experimental groups of GDX rats and control group of intact males were then tested in the elevated plus maze (EPM) and the open field test. 8-OH-DPAT treatment failed to modify anxiety-like behavior of GDX rats in the EPM as compared to the GDX rats given with oil solvent. NAN-190 injected alone or in combination with TP to GDX rats resulted in a significant anxiolyticlike effect as compared to the GDX given with oil solvent or TP application. Our data indicate that the combination of NAN-190 and TP is more effective than TP alone in GDX rats inducing a more profound anxiolytic-like effect in the EPM. Thus, the results of this study suggest that effects of 5-HT1A receptor agonist/antagonist can modify anxiety level in opposite direction in male rats after gonadectomy.