of all the unlabeled tachykinins tested ( substance p , physalaemin , substance k , eledoisin , kassinin , and neuromedin k ) substance p was the most potent inhibitor of [ 125i ] bolton-hunter substance p binding , with an ic50 of approximately 0.5 nm , indicating the presence of substance p-p binding sites .
C0039241
tachykinins
C0038581
substance k