Four sessions of immobilization stress induced anxiogenic behavioral disorders in rats, which were accompanied by decreases in glucocorticoid sensitivity, increases in MAO-B activity in brain tissue, increases in tolerance to glucose loading, and decreases in resistance to acute hypoxia. Alloxan diabetes was accompanied by a decrease in behavioral activity of rats in the open field test, with an increase in cerebral MAO-B activity. Preceding anxiogenic stress increased the extent of the alloxan-induced increase in cerebral MAO-B activity and the accompanying abnormalities in the rats' behavior, and also potentiated the hyperglycemic effect of alloxan.