The lack of effect of repeated treatment with antidepressant drugs on the 8-OH-DPAT-induced increase in the serum corticosterone concentration.

We studied the effect of repeated treatment (twice daily for 14 consecutive days) with the antidepressant drugs imipramine, citalopram and mianserin (all the drugs administered in a dose of 10 mg/kg po) on the 8-OH-DPAT-induced increase in the serum corticosterone concentration. We found that all those drugs affected neither basal nor 8-OH-DPAT-induced increase in the corticosterone concentration. These results suggest that long-term administration of the investigated antidepressant drugs does not modify the functional sensitivity of central 5-HT1A receptors.