Action of calcitonin gene‐related peptide upon bovine vascular endothelial and smooth muscle cells grown in isolation and co‐culture

Abstract

1 Bovine aortic endothelial cells (BAE) and smooth muscle cells (BASM) were grown separately and in co-culture. 2 Calcitonin gene-related peptide (CGRP) caused dose-dependent activation of adenylate cyclase in each cell type when grown in isolation. The concentration of CGRP causing half-maximal activation in BAE and BASM was 200nM and 310nm, respectively. 3 In cells grown in co-culture exposure to bradykinin produced dose-dependent elevations in cyclic GMP content which were maximal 1 min after application of the agonist.4 CGRP (1 nM-i gM) did not stimulate a rise in cyclic GMP in co-cultures.5 Displaceable CGRP binding was identified throughout the wall of the bovine aorta. 6 We conclude that CGRP receptors coupled to adenylate cyclase are present on BAE and BASM, but there is no coupling of these receptors to the release of any agent (such as endothelium-derived relaxing factor) that activates guanylate cyclase.

Effects of calcitonin gene-related peptide on normal and atheromatous vessels and on resistance vessels in the coronary circulation in humans.

“…Endotheliumdependent mechanisms have been demonstrated in vitro in rat aorta and mesenteric artery preparations6,20 and in human radial, coronary, gastric, and cerebral arteries.18 Endothelium-independent mechanisms have been demonstrated in bovine circumflex artery,2' cat middle cerebral and pial artery, human pial and rabbit pial arteries,22 and pig coronary arteries.23 In isolated bovine aortic endothelial cells, CGRP has been shown not to be coupled with endothelium-derived relaxing factor (EDRF) release. 24 Stimulation of EDRF production by the intracoronary administration of acetylcholine leads to a large increase in coronary flow,16 suggesting that either CGRP does not operate via an endothelium-dependent mechanism in human coronary artery or that appropriate receptors are mainly concentrated on the endothelium of epicardial vessels rather than arterioles, which would be supported by recent autoradiographic mapping studies of CGRP receptors by Coupe …”

Calcitonin gene‐related peptide activated ATP‐sensitive K+ currents in rabbit arterial smooth muscle via protein kinase A.

“…CGRP-induced dilatation of rat cerebral arteries in vivo is also inhibited by glibenclamide (Kitazono, Heistad & Faraci, 1993). KATP channels in arterial smooth muscle appear to be targets of a variety of synthetic and endogenous vasodilators (for review, see Nelson, 1993 well as the other vasodilators that appear to act in part through activation of KATP channels, has been shown to elevate intracellular levels of cAMP through activation of adenylyl cyclase (Crossman, Dashwood, Brain, McEwan & Pearson, 1990;Holzer, 1992 oonstant for Kta channels (Nelson, 1993) and about oneseventh the half-block constant for ATP-sensitive potassium (KATP) channels (Davies, Spruce, Standen & Stanfield, 1989 …”

Propofol stimulates nitric oxide release from cultured porcine aortic endothelial cells

“…Subsequently, 0.5ml icecold hydrochloric acid (0.1 N) was added and plates placed on ice for 20-30min to allow extraction of cyclic nucleotides. Cyclic GMP levels were determined by specific radioimmunoassay following acetylation (Crossman et al, 1990 Results ' In co-cultures of endothelial and smooth muscle cells, application of bradykinin (100 nM, 1 min) resulted in a significant increase in cyclic GMP production (control: 8.0 ± 2.8 fmol/106 cells, bradykinin 31.2 ± 11.4 fmol/106 cells, P < 0.01, n = 3). Similarly, application of sodium nitroprusside (SNP, 0.1 mM, 1 min) resulted in a large increase in cyclic GMP production (control: 8.0 ± 2.8, SNP: 91 + 31, P<0.01, n = 3).…”

“…Endothelial cells were used at either passage one or two (Bogle et al, 1991). Porcine aortic smooth muscle cells (PASMC) were isolated by a modified explant technique (Crossman et al, 1990). When confluent, endothelial cells were mixed with smooth muscle cells (1:1) and plated into 24 well plates for use 24h later.…”