Effects of sympathectomy on the in vitro alpha and beta-responses of the parotid gland.

Amylase and K+ resease were measured in slices obtained from innervated and sympathetically denervated rat parotid glands. Amylase release induced by noradrenaline was found to be increased after chronic denervation. The postjunctional component of supersensitivity to noradrenaline was evidenced by an increase in the maximal response to this agonist. The maximal response of denervated glands was blocked by propranolol 10(-5) M. On the other hand, chronic denervation did not modify the alpha-adrenoceptor-mediated response, K+ release, either in the presence or in the absence of ouabain. It is concluded that, after sympathetic denervation, postjunctional supersensitivity develops for the beta-adrenoceptor-mediated but not for the alpha-adrenoceptors-mediated effects of noradrenaline.