介导大鼠肺动脉舒张及大鼠输精管抽搐反应抑制的降钙素基因相关肽（CGRP）受体的药理学特性

Pharmacological characterization of CGRP receptors mediating relaxation of the rat pulmonary artery and inhibition of twitch responses of the rat vas deferens.

作者信息

Wisskirchen F M, Burt R P, Marshall I

机构信息

Department of Pharmacology, University College London.

出版信息

Br J Pharmacol. 1998 Apr;123(8):1673-83. doi: 10.1038/sj.bjp.0701783.

DOI:10.1038/sj.bjp.0701783

PMID:9605575

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1565337/

Abstract

CGRP receptors mediating vasorelaxation of the rat isolated pulmonary artery and inhibition of contractions of the rat isolated prostatic vas deferens were investigated using CGRP agonists, homologues and the antagonist CGRP8-37. 2. In the pulmonary artery, human (h)alpha-CGRP-induced relaxation of phenylephrine-evoked tone was abolished either by removal of the endothelium or by NG-nitro-L-arginine (10(-5) M). The inhibitory effect of NG-nitro-L-arginine was stereoselectively reversed by L- but not by D-arginine (10(-4) M). Thus, CGRP acts via nitric oxide released from the endothelium. 3. In the endothelium-intact artery, halpha-CGRP, hbeta-CGRP and human adrenomedullin (10(-10) - 3 x 10(-7) M), dose-dependently relaxed the phenylephrine-induced tone with similar potency. Compared with halpha-CGRP, rat amylin was around 50 fold less potent, while [Cys(ACM2,7)] halpha-CGRP (10(-7) - 10(-4) M) was at least 3000 fold less potent. Salmon calcitonin was inactive (up to 10(-4) M). 4 Human alpha-CGRP8-37 (3 x 10(-7) - 3 x 10(-6) M) antagonized halpha-CGRP (pA2 6.9, Schild plot slope 1.2+/-0.1) and hbeta-CGRP (apparent pKB of 7.1+/-0.1 for halpha-CGRP8-37 10(-6) M) in the pulmonary artery. Human beta-CGRP8-37 (10(-6) M) antagonized halpha-CGRP responses with a similar affinity (apparent pKB 7.1+/-0.1). Human adrenomedullin responses were not inhibited by halpha-CGRP8-37 (10(-6) M). 5. In the prostatic vas deferens, halpha-CGRP, hbeta-CGRP and rat beta-CGRP (10(-10) - 3 x 10(-7) M) concentration-dependently inhibited twitch responses with about equal potency, while rat amylin (10(-8) - 10(-5) M) was around 10 fold less potent and the linear analogue [Cys(ACM2,7)] halpha-CGRP was at least 3000 fold weaker. Salmon calcitonin was inactive (up to 10(-4) M). 6 The antagonist effect of halpha-CGRP8-37 (10(-5) 3 x 10(-5)) in the vas deferens was independent of the agonist, with pA2 values against halpha-CGRP of 6.0 (slope 0.9+/-0.1), against hbeta-CGRP of 5.8 (slope 1.1+/-0.1), and an apparent pKB value of 5.8+/-0.1 against both rat beta-CGRP and rat amylin. Human beta-CGRP8-37 (3 x 10(-5) - 10(-4) M) competitively antagonized halpha-CGRP responses (pA2 5.6, slope 1.1+/-0.2). The inhibitory effect of halpha-CGRP on noradrenaline-induced contractions in both the prostatic and epididymal vas deferens was antagonized by halpha-CGRP8-37 (pA2 5.8 and 5.8, slope 1.0+/-0.2 and 1.0+/-0.3, respectively). 7 The effects of halpha-CGRP and halpha-CGRP8-37 in both rat pulmonary artery and vas deferens were not significantly altered by pretreatment with peptidase inhibitors (amastatin, bestatin, captopril, phosphoramidon and thiorphan, all at 10(-6) M). The weak agonist activity of [Cys(ACM2,7)] halpha-CGRP in the vas deferens was not increased by peptidase inhibitors. 8 These data demonstrate that two different CGRP receptors may exist in the rat pulmonary artery and vas deferens, a CGRP1 receptor subtype in the rat pulmonary artery (CGRP8-37 pA2 6.9), while the lower affinity for CGRP8-37 (pA2 6.0) in the vas deferens is consistent with a CGRP2 receptor.

摘要

使用降钙素基因相关肽（CGRP）激动剂、同源物及拮抗剂CGRP8 - 37，研究了介导大鼠离体肺动脉血管舒张及抑制大鼠离体前列腺输精管收缩的CGRP受体。2. 在肺动脉中，去除内皮或使用NG - 硝基 - L - 精氨酸（10⁻⁵ M）可消除人（h）α - CGRP诱导的去氧肾上腺素诱发张力的舒张。NG - 硝基 - L - 精氨酸的抑制作用可被L - 精氨酸而非D - 精氨酸（10⁻⁴ M）立体选择性逆转。因此，CGRP通过内皮释放的一氧化氮发挥作用。3. 在内皮完整的动脉中，α - CGRP、β - CGRP和人肾上腺髓质素（10⁻¹⁰ - 3×10⁻⁷ M）以剂量依赖方式舒张去氧肾上腺素诱导的张力，效力相似。与α - CGRP相比，大鼠胰淀素效力约低50倍，而[Cys(ACM2,7)]α - CGRP（10⁻⁷ - 10⁻⁴ M）效力至少低3000倍。鲑鱼降钙素无活性（高达10⁻⁴ M）。4. 人α - CGRP8 - 37（3×10⁻⁷ - 3×10⁻⁶ M）在肺动脉中拮抗α - CGRP（pA2 6.9，希尔斜率1.2±0.1）和β - CGRP（α - CGRP8 - 37 10⁻⁶ M时表观pKB为7.1±0.1）。人β - CGRP8 - 37（10⁻⁶ M）以相似亲和力拮抗α - CGRP反应（表观pKB 7.1±0.1）。人肾上腺髓质素反应未被α - CGRP8 - 37（10⁻⁶ M）抑制。5. 在前列腺输精管中，α - CGRP、β - CGRP和大鼠β - CGRP（10⁻¹⁰ - 3×10⁻⁷ M）浓度依赖性抑制抽搐反应，效力大致相同，而大鼠胰淀素（10⁻⁸ - 10⁻⁵ M）效力约低10倍，线性类似物[Cys(ACM2,7)]α - CGRP至少弱3000倍。鲑鱼降钙素无活性（高达10⁻⁴ M）。6. α - CGRP8 - 37（10⁻⁵ - 3×10⁻⁵）在输精管中的拮抗作用与激动剂无关，对α - CGRP的pA2值为6.0（斜率0.9±0.1），对β - CGRP为5.8（斜率1.1±0.1），对大鼠β - CGRP和大鼠胰淀素的表观pKB值为5.8±0.1。人β - CGRP8 - 37（3×10⁻⁵ - 10⁻⁴ M）竞争性拮抗α - CGRP反应（pA2 5.6，斜率1.1±0.2）。α - CGRP对前列腺和附睾输精管中去甲肾上腺素诱导收缩的抑制作用被α - CGRP8 - 37拮抗（pA2分别为5.8和5.8，斜率分别为1.0±0.2和1.0±0.3）。7. 用肽酶抑制剂（抑氨肽酶素、贝抑素、卡托普利、磷酰胺素和硫磷酰胺，均为10⁻⁶ M）预处理后，大鼠肺动脉和输精管中α - CGRP及α - CGRP8 - 37的作用未显著改变。肽酶抑制剂未增强[Cys(ACM2,7)]α - CGRP在输精管中的弱激动剂活性。8. 这些数据表明，大鼠肺动脉和输精管中可能存在两种不同的CGRP受体，大鼠肺动脉中为CGRP1受体亚型（CGRP8 - 37 pA2 6.9），而输精管中对CGRP8 - 37亲和力较低（pA2 6.0）与CGRP2受体一致。