Pharmacological evidence for the role of central alpha 1B-adrenoceptors in the motor activity and spontaneous movement of mice.

Central alpha 1-noradrenergic neurotransmission has been shown to be an important complement of dopaminergic transmission in the control of motor activity but the identity of the responsible alpha 1 receptor subtype has not yet been identified. This was investigated in the present experiment by measuring the effects of intraventricular administration of a series of alpha 1 antagonists varying in affinities for the three known receptor subtypes--1a, 1b and 1d--on active behavior in mice in response to a cage change. It was found that the potency of the drugs to block both gross and small movements correlated highly with published affinities for the cloned 1b receptor but not for those of either the cloned 1a or 1d receptors. It is concluded that central alpha 1B receptors are critically involved in the mediation of the (nor)adrenergic influence on active behavior, a finding which has implications for basic and clinical research in both movement and mood disorders.