Eledoisin, an undecapeptide of mollusk origin, with the sequence pGlu-Pro-Ser-Lys-Asp-Ala-Phe-Ile-Gly-Leu-Met-NH2, is a member of the tachykinin family of neuropeptides. It was first isolated from the posterior salivary glands of two mollusk species, Eledone muschata and E. aldovandi, belonging to Cephalopoda. Other tachykinins from nonmammalian sources include kassinin and physalaemin. These peptides exhibit a wide and complex spectrum of pharmacological and physiological activities such as powerful vasodilation, hypertensive action, and stimulation of extravascular smooth muscle.