the apparent dependence of intact catecholamine stores and functional alpha 2-adrenoreceptors for demonstration of the low affinity site for propranolol in this preparation suggests that the low affinity site reflects the ability of beta-adrenergic blockers to antagonize an action of isoproterenol upon presynaptic beta-receptors .
C0007412
catecholamine
C0022245
isoproterenol