Repeated administration of antidepressant drugs reduces regional somatostatin concentrations in rat brain

A possible role for somatostatin in affective disorders is suggested by its low concentration in cerebrospinal fluid of patients with depression. Therefore, we studied the regional effects of antidepressant drugs and antimanic agents on somatostatin concentrations in rat brain. Repeated, but not acute, administration of clomipramine, a specific serotonin uptake inhibitor, caused a highly significant, widespread reduction in somatostatin levels. Somatostatin content was similarly reduced in the hypothalamus, and midbrain and thalamus following repeated administration of zimelidine, another specific serotonin uptake inhibitor. Repeated administration of either imipramine, maprotiline, mianserin, carbamazepine or zotepine were without effect on somatostatin levels. These results suggest that somatostatin in the brain might be involved in therapeutic effects of some of antidepressant drugs.