Calcitonin gene-related peptide in rat arterial and venous vessels: sensitivity to capsaicin, bradykinin and FMLP.

Sensitivity of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) to capsaicin was investigated in different arterial and venous tissues (mesenteric, renal and femoral artery and vein and carotid artery and jugular vein) of the rat. In vivo capsaicin pre-treatment depleted or reduced tissue CGRP-LI in all the vessels examined with the exception of the carotid artery. Likewise, in vitro exposure to capsaicin evoked release of CGRP-LI from all vessels, excluding the carotid artery. Remarkable amount of CGRP-LI sensitive to capsaicin was present in both mesenteric artery and vein as compared to the other vascular tissues. Endogenous (bradykinin) or exogenous (N-formyl-methionyl-leucyl-phenylalanine) proinflammatory agents, were found to release CGRP-LI from mesenteric veins.