A two-week treatment with antidepressants does not increase the density of 3H-prazosin binding sites in the cerebral cortex of elderly rats.

The effect of repeated administration of antidepressants (imipramine, amitriptyline, citalopram) on the 3H-prazosin binding to alpha 1-adrenoceptors in the cerebral cortex of elderly (12-14-month old) rats was studied. Additionally, the effect evoked by imipramine was also studied in their young (2-3-month old) counterparts. Imipramine increased the Bmax value by 27% in young animals, while imipramine, amitriptyline and citalopram did not change the 3H-prazosin binding (Bmax, KD) in elderly rats. The obtained results demonstrate that the ability of antidepressants to increase the number of alpha 1-adrenoceptors in the rat cerebral cortex disappears with age.