Evidence for decreased calcitonin gene-related peptide (CGRP) receptors and compromised responsiveness to CGRP of fetoplacental vessels in preeclamptic pregnancies.

Calcitonin gene-related peptide (CGRP) is a potent vasodilatory peptide, and its concentration is increased in both maternal and fetal circulation during late pregnancy. The present study was designed to investigate the expression of CGRP receptor components, calcitonin receptor-like receptor (CRLR), and receptor activity modifying protein 1 (RAMP1), and the relaxation response to CGRP in fetoplacental vessels from normotensive pregnant women and women with preeclampsia. Results showed that: 1) mRNA for both CRLR and RAMP1 was expressed in fetoplacental vessels from normal pregnancies; however, these mRNA expressions were substantially reduced in the vessels from preeclamptic women; 2) CRLR and RAMP1 proteins were abundantly expressed in the endothelium and smooth muscle layer of the fetoplacental vessels, as well as the trophoblast cells in normal placentas.