Distribution of adrenomedullin (AM)-containing perivascular nerve fibers was studied in rat mesenteric arteries. Many fibers containing AM-like immunoreactivity (LI) were observed in the adventitia. AM-LI fibers were abolished by cold storage denervation or capsaicin but not 6-hydroxydopamine. Double immunostainings showed colocalization of AM-LI with calcitonin gene-related peptide (CGRP)-LI. The dorsal root ganglia had many AM-positive cells and AM mRNA detected by RT-PCR. Electron microscopy study revealed high proportions of immunogold labeling for AM and colocalization of both AM-LI and CGRP-LI in unmyelinated nerve axons. These results suggest that AM-containing perivascular nerves are distributed in the rat mesenteric artery.
Copyright 2004 Elsevier Inc.