Role of D-1 and alpha(1) receptors in the enhanced locomotor response to dopamine D-2-like receptor stimulation induced by repeated electroconvulsive shock

We previously reported that, in rats chronically treated with the antidepressant drug imipramine, the enhanced locomotor response to the D-2-like receptor agonist quinpirole became less sensitive to the inhibitory effect of the D-1 receptor antagonist SCH 23390 and more sensitive to the inhibitory effect of the alpha(1) receptor antagonist prazosin. In this study, we show that in electroconvulsive shock-treated rats these antagonists behave in the opposite manner to that observed in imipramine-treated rats, with SCH 23390 being highly effective and prazosin ineffective in antagonizing the locomotor response to quinpirole. The possibility that these differences may reflect some of the clinical characteristics of these antidepressant treatments is discussed.