[Effect of tamoxifen on anxiety in ovariectomized and intact female rats]

The effect of tamoxifen (estrogen receptor modulator) administered in a daily dose of 10 mg/kg (i.p.) over 14 days on the behavioral state of female rats has been studied in various phase of the sexual cycle and in the state of estrogen deficiency. In the elevated-plus-maze and open-field tests, the administration of tamoxifen to intact rats was accompanied by anxiolytic and/or anxiogenic effects, depending on the phase of the sexual cycle. The ovaryectomy led to a sharp increase in the anxiety. The chronic administration of tamoxifen in ovaryectomized female rats produced a stronger anxiolytic effect in comparison to 17beta3-estradiol. The results show that tamoxifen produces a modulating action on the state of anxiety, which depends on the estrogen level in the blood.