Hasbak Philip, Saetrum Opgaard Ole, Eskesen Karen, Schifter Søren, Arendrup Henrik, Longmore Jenny, Edvinsson Lars
Department of Clinical Experimental Research, University Hospital of Copenhagen, Glostrup, Denmark.
J Pharmacol Exp Ther. 2003 Jan;304(1):326-33. doi: 10.1124/jpet.102.037754.
Calcitonin gene-related peptide (CGRP), adrenomedullin (AM), and amylin are structurally related peptides mediating vasorelaxation in the coronary circulation possibly via CGRP receptors (subtypes 1 or 2). Functional CGRP1 receptors appear to consist of at least three different kinds of proteins: the calcitonin receptor-like receptor (CRLR), receptor-activity-modifying proteins (RAMPs) and the receptor component protein (RCP). No CGRP2 receptor has yet been cloned. Using reverse transcriptase - polymerase chain reaction, the presence of mRNA sequences encoding CRLR, RCP and RAMPs was demonstrated in human coronary arteries. Relaxant responses were studied on isolated segments of coronary arteries after precontraction with U46619 (9,11-dideoxy-11alpha,9alpha-epoxymethano-prostaglandin F(2alpha)). The human peptides alphaCGRP, AM, and amylin induced relaxation with mean pEC50 values of 8.6, 6.8, and 6.3 M, respectively. Preincubation with alphaCGRP(8-37) (10(-7) -10(-5) M) and a novel nonpeptide CGRP antagonist "Compound 1" (WO98/11128) (10(-7)-10(-5) M) caused a dose-dependent rightward shift of the concentration-response curves for alphaCGRP with pA(2) values of 7.0 and 7.1, respectively. Preincubation with alphaCGRP(8-37) (10(-6) M) and Compound 1 (10(-6) M) caused significant rightward shift of the concentration-response curves for AM and amylin as well with pK B values between 6.6 and 7.5. Preincubation with AM(22-52) had no antagonistic effect on the AM and amylin response, neither did diacetoamidomethyl cysteine CGRP cause any concentration dependent (10(-11)-10(-6) M) dilatation. In conclusion, mRNA for the components forming CGRP1 and AM receptors was detected in the human left anterior descending coronary arteries. alphaCGRP, AM, and amylin mediated vasorelaxation via the CGRP1 receptor. Compound 1 acted as a nonpeptide antagonist at the CGRP1 receptor and could thus become a tool for the study of CGRP-mediated functional responses in human tissue.
降钙素基因相关肽（CGRP）、肾上腺髓质素（AM）和胰淀素是结构相关的肽类，可能通过CGRP受体（1型或2型亚型）介导冠状动脉循环中的血管舒张。功能性CGRP1受体似乎至少由三种不同的蛋白质组成：降钙素受体样受体（CRLR）、受体活性修饰蛋白（RAMP）和受体成分蛋白（RCP）。尚未克隆出CGRP2受体。使用逆转录聚合酶链反应，在人冠状动脉中证实了编码CRLR、RCP和RAMP的mRNA序列的存在。在用U46619（9,11-二脱氧-11α,9α-环氧甲叉前列腺素F(2α)）预收缩后，对分离的冠状动脉节段的舒张反应进行了研究。人肽αCGRP、AM和胰淀素分别以平均pEC50值8.6、6.8和6.3 M诱导舒张。用αCGRP(8 - 37)（10(-7) - 10(-5) M）和新型非肽CGRP拮抗剂“化合物1”（WO98/11128）（10(-7) - 10(-5) M）预孵育导致αCGRP浓度-反应曲线呈剂量依赖性右移，pA(2)值分别为7.0和7.1。用αCGRP(8 - 37)（10(-6) M）和化合物1（10(-6) M）预孵育也导致AM和胰淀素的浓度-反应曲线显著右移，pK B值在6.6和7.5之间。用AM(22 - 52)预孵育对AM和胰淀素的反应没有拮抗作用，二乙酰氨基甲基半胱氨酸CGRP也未引起任何浓度依赖性（10(-11) - 10(-6) M）的扩张。总之，在人左前降支冠状动脉中检测到了形成CGRP1和AM受体的成分的mRNA。αCGRP、AM和胰淀素通过CGRP1受体介导血管舒张。化合物1作为CGRP1受体的非肽拮抗剂，因此可能成为研究人体组织中CGRP介导的功能反应的工具。
