Co-administration of RJR-2403 with low dose of 17β-estradiol on spatial learning in ovariectomized rats

Abstract

The aim of this work was to study the influence of stimulation or blockade Na7-cholinoreceptors on dynamics of spatial learning in water Morris maze and on behavior in the «open field» test in adult ovariectomized (OVX) females given with a low dose of 17β-estradiol. Agonist of Na7-cholinoreceptors — RJR-2403 (1,0 mg/kg, i.p.) or antagonist of Na7-cholinoreceptors — mecamylamine (1,0 mg/kg, i.p.) treated chronically (14 days) alone and in a combination with low dose of 17β-estradiol (0,5 µ/rat, s.c.) to OVX rats. Co-administration of RJR-2403 with low dose of 17β-estradiol completely restored impaired spatial learning in water Morris maze in OVX females. Moreover, OVX rats treated with RJR-2403 and low dose of 17β-estradiol demonstrated increased exploratory and grooming behavior in the «open field» test. Both mecamylamine alone and in combination with low dose of 17β-estradiol failed to influence on spatial learning and failed to modify behavior in the «open field» test in OVX rats. The results of the present study suggest a positive effect of RJR-2403 in combination with low dose of 17β-estradiol on spatial learning at estrogen deficiency.