Effect of Surfagon on Open Field and Elevated Plus Maze Behavior of Gonadectomized and Non-Gonadectomized Male Rats.

We studied the effect of gonadotropin-releasing hormone agonist surfagon (2 µg/kg, once, intraperitoneally) on anxious behavior of adult gonadectomized and non-gonadectomized male rats. It was shown that surfagon significantly increased anxiety of both gonadectomized and non-gonadectomized rats in the open-field test and in elevated plus maze.

[Comparative analysis of the effects of estrogens and tamoxifen on the brain higher functions].

At present, it is commonly accepted that estrogens modulate both cognitive and psycho-emotional status. Induced or natural hypoestrogeny is frequently accompanied by a complex of pathological states including suppressed state, anxiety, and weeping, sometimes with the development of depression. It is established that a substituting hormonal therapy in some cases favors restoration of the cognitive function and provides correction of affective disorders. Unfortunately, this therapy is accompanied by side effects and has some counterindications, which restricts its use in clinical practice. For this reason, it is of interest to try alternative agonists/antagonists of estrogen receptors possessing selective activity with respect to estrogen-sensitive tissues (including CNS), but these agents are still insufficiently studied. The given review describes the effect of estrogens on the brain functions, considers the mechanisms of action, and analyzes undesired side effects accompanying long-term administration. In particular, the results obtained in recent years concerning the effect of tamoxifen on the brain functions are summarized.

[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.