Autoradiographic localization of receptors in the mammalian cardiovascular system.

1. Autoradiographic techniques have been used to examine the location of beta-adrenoceptors in the heart and beta-adrenoceptors, substance P receptors and muscarinic cholinoceptors in blood vessels. 2. Both beta 1-adrenoceptors and beta 2-adrenoceptors were present in guinea-pig and human heart, on the myocardium and associated with the cardiac nerves and blood vessels. 3. Nerves on the vasculature and vascular smooth muscle contained beta-adrenoceptors and muscarinic cholinoceptors. 4. Receptors for substance P and beta-adrenoceptors, but not muscarinic cholinoceptors were present on endothelial cells.