Preferential noradrenergic innervation of alpha-adrenergic receptors in vascular smooth muscle

Abstract

In the isolated perfused hindlimb preparation of the dog, pressor responses to norepinephrine (NE) are mediated by postsynaptic α1- and α3-adrenergic receptors. Results obtained using preferential α1- and α1-adrenergic receptor antagonists suggest that the α1-subtype is predominantly innervated while both α1,- and αr-adrenergic receptor subtypes in vascular smooth muscle are accessible to circulating agonists and antagonists. Preliminary studies in the isolated perfused cat spleen support these in rivo findings in the dog. In contrast to vascular smooth muscle, the cat nictitating membrane appears to contain only α1,-adrenergic receptors postsynaptically. © 1981 American Heart Association, Inc.