Calcitonin gene-related peptide and neural control of vascular tone

Abstract

Rat mesenteric resistance blood vessels are innervated by nonadrenergic, noncholinergic (NANC) vasodilator nerves. In vitro pharmacological, biological and immunohistochemical studies have provided evidence that the calcitonin gene related peptide (CGRP), a 37 amino acid peptide translated by the calcitonin gene, has a potent vasodilator effect and acts as a vasodilator neurotransmitter for NANC vasodilator nerves. The CGRP-containing vasodilator nerves inhibit adrenergic nerve-mediated vasoconstriction through direct relaxation of vascular smooth muscle, while adrenergic nerves suppress the neurotransmission of CGRP-containing nerves by inhibiting CGRP release from the nerve. Thus, CGRP-containing nerves and adrenergic nerves control vascular tone with reciprocal interferrences. In in vivo studies, spinal cord (T9-12) stimulation of pithed rats produced a NANC depressor response mediated by endogenous CGRP, suggesting that CGRP-containing nerves are regulated by the central nervous system. The malfunction of CGRP-containing vasodilator nerves may be involved in cardiovascular diseases such as essential hypertension, coronal vasospasm, cerebral vasospasm and Renaud's phenomenon. It is suggested that the CGRP-containing vasodilator nerves play an important role in the regulation of vascular tone.