Neuromedin L: a novel mammalian tachykinin identified in porcine spinal cord.

A novel mammalian tachykinin, designated "neuromedin L", has been isolated from porcine spinal cord by using bioassay for a tachykinin-like effect on contractility of smooth muscle preparation from guinea pig ileum. By microsequencing, the peptide has been determined to be His-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met-NH2. This structure has been confirmed by synthesis. Neuromedin L is found to elicit a prompt stimulant activity on guinea pig ileum in a manner similar to that of substance P, and to have remarkable sequence homology to kassinin as well as neuromedin K, which we have recently identified as a mammalian tachykinin. These facts suggest that neuromedin L may participate in neural transmission in the same manner as other members of the mammalian tachykinin family, such as substance P and neuromedin K.