[Influence of agonist and antagonist Nalpha7-cholinoreceptors on active avoidance learning and gonadal hormones levels in ovariectomized female rats].

: The aim of this work was to study the influence of co-administration of agonist and antagonist of Nalpha7-cholinoreceptors with low dose of 17beta-estradiol on dynamics of acquisition and retention in active avoidance test, on the behavior in the "open field" test, as well as tropic and gonadal hormones levels in ovariectomiczed female rats. Antagonist of Nalpha7-cholinoreceptors - RJR-2403 (1.0 mg/kg, i. p.) and antagonist of Nalpha7-cholinoreceptors - mecamylamine (1.0 mg/kg, i. p.) were administered chronically (14 days) isolated or in combination with low dose of 17beta-estradiol (0.5 m/rat, s. c.) to ovariectomized rats. It was revealed that RJR-2403 in combination with low dose of 17beta -estradiol completely restored impairments in mechanisms of dynamics of active avoidance performance and increased exploratory and grooming behavior in the "open field" test in ovariectomized rats. Moreover, RJR-2403 treatment decreased follitropine and lutropine levels and increased estradiol level in the blood serum in ovariectomized rats. Administration ofmecamylamine alone or in combination with low dose of 17beta-estradiol in ovariectomiczed rats failed to influence on dynamics of passive avoidance learning and failed to modify behavior in the "open field" test. The results of the present study suggest positive effect of Nalpha7-cholinoreceptors stimulation on background of low dose for 17beta-estradiol on active avoidance learning and tropic and gonadal hormones levels at estrogen deficiency.