MAXADILAN BINDS TO MEMBRANE-FRACTIONS OF BRAIN-TISSUE

Maxadilan is a potent vasodilator peptide isolated from salivary gland s extracts of the hematophagous sand fly. Besides effects on the cutan eous vasculature, it has also been shown to relax rabbit aortic rings while elevating levels of cAMP. As a result of the effects on the skin and aorta, it was elected to undertake an examination of the tissue d istribution of binding sites for maxadilan. In addition to specific bi nding in rabbit aorta and spleen, binding was detected in brain from v arious species including human, bovine, rabbit, rat and mouse with a k D of between 85 and 201 pM. Competitive displacement of [I-125] maxadi lan by a number of known vasoconstrictor peptides, vasodilator peptide s and small molecule receptor ligands did not occur in the rabbit brai n preparation. These results suggest the presence of specific binding sites in mammalian tissue for maxadilan whose endogenous ligand remain s unknown. (C) 1995 Academic Press, Inc.