Neurophysiological evidence for tricyclic antidepressant-induced decreased beta-adrenergic responsiveness in the rat hippocampus.

A study was made in rats of the effects of chronic treatment with the tricyclic antidepressant agent imipramine on the increase in the population spike amplitude produced by the beta-adrenergic receptor agonist isoproterenol in the 'in vitro' slice preparation of the hippocampus. A significant reduction of 39% and 44% of the population spike increase was observed at 5 X 10(-7) M and 1 X 10(-6) M isoproterenol respectively in rats treated for 28 days with 10 mg/kg i.p. imipramine.