Chronic imipramine, L-sulpiride and mianserin decrease corticotropin releasing factor levels in the rat brain.

Among clinically effective antidepressant drugs, the action mechanism of mianserin has recently been related to variations in corticotropin releasing factor (CRF) levels in the rat locus coeruleus. We describe a specific effect on CRF levels after chronic treatment with different antidepressants: mianserin (10 mg/kg), imipramine (20 mg/kg), both for 21 days, or L-sulpiride (1 mg/kg) for 15 days. While all antidepressants used greatly decreased CRF concentrations in the hypothalamus, only mianserin decreased CRF concentrations by 40% in extrahypothalamic sites. Acute treatments failed to modify CRF levels. Chronic treatment with mianserin did not affect CRF density either in the hypothalamus or the extrahypothalamic areas. This new finding may add another facet to the therapeutic action of certain antidepressants and in particular to the atypical profile of mianserin.