Chronic haloperidol causes increase in salivary response and alpha 1-adrenoceptors in submandibular gland of the rat.

The effect of chronic haloperidol on the receptor-secretion coupling of the submandibular glands of the rat was studied. After injection of 2 mg/kg haloperidol daily for 7 days, the dose-response curve to L-noradrenaline was displaced to the left, with lowering of the threshold and enhancement of the maximal response. This was accompanied by a 73% increase in alpha 1-adrenoceptors in the glands. The effect was selective, since no changes were observed in alpha 2- and beta-adrenoceptors.