Parallel changes in the sensitivity of gamma-aminobutyric acid and noradrenergic receptors following chronic administration of antidepressant and GABAergic drugs. A possible role in affective disorders.

Chronic treatment with the antidepressants imipramine or nomifensine, or the gamma-aminobutyric acid (GABAergic) agents, baclofen or THIP, produced a decrease in the Bmax for binding sites of GABAergic and noradrenergic receptors. Chronic treatment with imipramine or nomifensine produced a decrease in the Bmax of both binding of [3H]dihydroalprenolol and [3H]GABA receptors in the cerebral cortex and hippocampus. Chronic treatment with baclofen or THIP also produced a decrease in the Bmax of binding of [3H]dihydroalprenolol receptor in the cerebral cortex and hippocampus. These results suggest a possible link between the GABAergic and noradrenergic systems, which may be important in understanding the mechanism of action of antidepressant drugs, and suggests a possible role for GABA in affective disorders.