Involvement of Receptor Activity-Modifying Protein 3 (RAMP3) in the Vascular Actions of Adrenomedullin in Rat Mesenteric Artery Smooth Muscle Cells.

CALCB, ADM, and ADM2 are potent vasodilators that share a seven-transmembrane GPCR, calcitonin receptor-like receptor (CALCRL), whose ligand specificity is dictated by the presence of one of the three receptor activity-modifying proteins (RAMPs). We assessed the relative pharmacologic potency of these peptides in mesenteric artery smooth muscle cells (VSMCs) and the specific RAMP that mediates the effect of ADM in VSMCs. VSMCs, with or without RAMP knockdown, were treated with CALCB, ADM, or ADM2 in the presence or absence of their antagonists, CALCB8-37, ADM22-52, and ADM217-47, respectively, to assess the relative effect of peptides on cAMP production and their pharmacologic potency.