CALCITONIN-GENE-RELATED PEPTIDE (CGRP)1 RECEPTOR MEDIATES VASODILATION IN THE RAT ISOLATED AND PERFUSED KIDNEY

The vasodilator activity of rat (r) alpha and beta calcitonin gene-rel ated peptide (CGRP) as compared to the structurally related peptide, r Amylin, Cys(ACM)2,7!human (h)CGRP and salmon calcitonin, was investig ated in the rat isolated and perfused kidney which vascular tone was i ncreased by 3 muM noradrenaline. The order of potency in producing vas odilation was alphaCGRP>betaCGRP>>rAmylin. Cys(ACM)2,7!hCGRP and salm on calcitonin were ineffective. The activity of alpha and beta forms o f rCGRP and rAmylin was antagonized by hCGRP(8-37), a CGRP1 receptor a ntagonist, at a concentration which did not affect acetylcholine-induc ed vasodilation. These results indicate the involvement of CGRP1 recep tor in the CGRP-induced vasodilation in the rat kidney.