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新近研究发现 ,肾上腺髓质素 (adrenomedullin ,ADM)和降钙素基因相关肽 (calcitoningene relatedpeptide,CGRP)均能与降钙素受体样受体 (calcitoninreceptor likereceptor,CRLR)结合 ,其配体特异性由受体活性修饰蛋白 (re ceptoractivity modifyingprotein ,RAMP)调控。本工作在离体培养的大鼠胸主动脉血管平滑肌细胞 (vascularsmoothmus clecells,VSMCs)上观察ADM和CGRP受体脱敏现象 ,以探讨CRLR/RAMP假说在心血管组织方面的意义。用无血清培养基 (serum freemedium ,SFM)和含有 10 -8mol/LADM、CGRP和肾上腺髓质素前体原N 末端 2 0肽 (proad renomedullinN terminal2 0peptide ,PAMP)的SFM培养 ,再用 10 -8mol/LADM或CGRP和磷酸二脂酶的抑制剂异丙基次黄苷 (isobutyrylmethyxanthine ,IBMX)与VSMCs进行第二次孵育 ,然后收集细胞 ,测定VSMCscAMP含量。 10 -8mol/LADM、CGRP和PAMP单独与VSMCs孵育 ,VSMCscAMP含量分别较SFM组高 191% (P <0 0 1)、3 85 % (P <0 0 1)和 67% (P <0 0 5 ) ;预先用 10 -8mol/LADM或CGRP与VSMCs孵育可降低随后的CGRP刺激VSMCs产生cAMP ,分别较单次CGRP孵育少 4 4 % (P <0 0 5 )和 4 8% (P <0 0 1) ;预先用 10 0nmol/L蛋白激酶A (PKA)抑制剂H 89处理VSMCs,可完全阻断ADM?
Recent studies have found that both adrenomedullin (ADM) and calcitonin gene related peptide (CGRP) can bind to calcitonin receptor-like receptor (CRLR), and its ligand specificity Regulated by receptor activity modifying protein (reptptory activityprotein, RAMP). In this study, we observed the desensitization of ADM and CGRP receptors on cultured rat thoracic aorta vascular smooth muscle cells (VSMCs) to explore the significance of the CRLR / RAMP hypothesis in cardiovascular tissue. The cells were cultured in serum free medium (SFM) and SFM containing 10 -8 mol / L ADM, CGRP and proadrenomedullin N terminal 2 peptide (PAMP) / LADM or isobutyrylmethyxanthine (IBMX), a inhibitor of CGRP and phosphodiesterase, was incubated with VSMCs for a second incubation. Cells were then harvested and the VSMCscAMP content determined. VSMCs were incubated with 10 -8 mol / L ADM, CGRP and PAMP alone. VSMCscAMP levels were 191% (P <0.01), 85% (P <0.01) and 67% (P <0 05) ). Preincubation of VSMCs with 10 -8 mol / L ADM or CGRP decreased the CAMP-stimulated VSMCs to produce cAMP, which was 44% (P <0.05) and 48% (P <0 0) lower than that of CGRP alone 1); Pretreatment of VSMCs with 10 0 nmol / L protein kinase A (PKA) inhibitor H 89 completely blocked ADM?