Maxadilan, the Vasodilator from Sand Flies, Is a Specific Pituitary Adenylate Cyclase Activating Peptide Type I Receptor Agonist

Abstract

Maxadilan is a potent vasodilator peptide isolated from salivary gland lysates of the sand fly Lutzomyia longipalpis, a vector of leishmaniasis. The peptide aids the fly in obtaining blood from the skin of its vertebrate hosts but the mammalian receptor through which this insect ligand acts was unknown. We demonstrate that maxadilan is an agonist of the type I receptor for pituitary adenylate cyclase activating peptide, a neuropeptide with vascular activity. This surprising observation is a unique example of convergent evolution from a functional standpoint as these two peptides do not share significant sequence homology.