Autoradiographic localization of muscarinic receptors in rabbit carotid body.

Muscarinic receptors in the rabbit carotid body were studied utilizing the specific muscarinic antagonist. [3H]quinuclidinyl benzilate. Biochemical and autoradiographic assays of ligand binding showed that receptor numbers and distributions remained unchanged following degeneration of axons and terminals of the carotid sinus nerve. The data suggest that muscarinic receptors are associated with carotid body parenchymal cells and are absent on afferent nerve terminals.