Reduced levels of calcitonin gene-related peptide-like immunoreactivity in human brain vessels after subarachnoid haemorrhage.

Human cerebral vessels were found to contain calcitonin gene-related peptide (CGRP)-like immunoreactivity (-LI) which in the reversed phase HPLC co-eluted with authentic human alpha-CGRP. The level was significantly lower in arteries removed from patients who had died from a subarachnoid haemorrhage (SAH) as compared to patients who died of a coronary infarction. On a molar basis human alpha-CGRP was more potent than human beta-CGRP to dilate human brain vessels and to dilate vasoconstriction elicited by whole blood. It is suggested that the trigemino-cerebrovascular system storing CGRP-LI may be involved in the pathophysiology of SAH in man.