[Co-administration of NAN-190 with low dose of testosterone propionate improves passive avoidance performance in rats...

We have studied the effect of stimulation or blockade of the 5-HT(1A) receptors on the passive avoidance performance and open-field test behavior in gonadectomized (GDX) male rats of middle age treated with a low dose of testosterone propionate. of The 5-HT(1A) receptor agonist 8-OH-DPAT (0.05 mg/kg, s.c.) or 5-HT(1A) receptor antagonist NAN-190 (0.1 mg/kg, i.p.) were chronically (for 14 days) administered alone and in a combination with low dose of testosterone propionate (0.5 mg/kg, s.c.) in GDX rats of middle age (12 - 15 months). The co-administration of NAN-190 with low dose of testosterone propionate completely restored impaired passive avoidance performance in GDX males of middle age. Moreover, GDX rats of middle age treated with NAN-190 and low dose of testosterone propionate demonstrated increased exploratory and grooming behavior in the open-field test. Both 8-OH-DPAT alone and in combination with low dose of testosterone propionate markedly impaired passive avoidance learning and failed to modify behavior in the open-field test in GDX rats of middle age. The results of the present study are indicative of a positive effect of NAN-190 in combination with low dose of testosterone propionate on the passive avoidance learning at androgen deficiency in male rats of middle age.