evaluation of the relative binding affinities of various piis for mammalian alpha-adrenergic receptors , as well as the ability of various antagonists to block pii binding , strongly suggested that the active piis are affecting a class of octopamine receptors distinct from mammalian alpha 1- or alpha 2-adrenergic receptors .
C0034784
alpha-adrenergic receptors
C0001639
alpha 2-adrenergic