Increase in rat cortical [3H]naloxone binding site density after chronic administration of antidepressant agents.

Given chronically, the first and second generation antidepressants imipramine and citalopram, and antidepressant neuroleptics levomepromazine and chlorprothixene, elevated moderately but significantly (by 15-30%) the density of [3H]naloxone binding sites in rat cerebral cortical membranes. There were only small non-significant changes in Kd values.