Receptors for substance P and neurokinins. Correlation between binding and biological activities

The biological activities of neurokinin-related peptides were compared with their binding affinities measured in various laboratories. A positive significant correlation was demonstrated between the relaxation of the dog carotid artery and the binding of Bolton-Hunter [125I]substance P to rat brain synaptosomes, the contractions of the rat duodenum and the rabbit pulmonary artery and the binding of Bolton-Hunter [125I]neurokinin A to duodenum smooth muscle plasma membranes, and the contraction of the rat portal vein and the binding of [125I]Bolton-Hunter NH-senktide to rat cerebral cortex membranes.