Immunohistochemical detection of calcitonin gene-related peptide receptor (CGRPR)-1 in the endothelium of human coronary artery and bronchial blood vessels

The potent vasodilatory peptide, calcitonin gene-related peptide (CGRP) is present in the innervation of vascular tissue. The actions of CGRP occur vi a a receptor, CGRP receptor(R)-1, which is also a target for the cardioprot ective peptide adrenomedullin. The human Version of the pharmacologically-d efined CGRPR-1 has been cloned but its distribution and cellular location i s unknown. A rabbit antibody was generated to a synthetic peptide that corr esponds to the C-terminus of human CGRPR-1 Immunochemical analysis of the h uman cell-line, SK-N-MC, which exhibits functional expression of the CGRPR- 1 confirmed the antibody's specificity. The antiserum revealed specific sta ining in the endothelium of human coronary arteries. The vascular smooth mu scle and ventricular myocardium were not immunoreactive. In bronchial blood Vessels CGRPR-1-immunoreactivity was detected in the endothelium of the Ve nules and not in the arterioles, which is particularly relevant for elucida ting the putative role of CGRP in inflammation in this tissue. (C) 2001 Har court Publishers Ltd.