肾上腺髓质素对豚鼠心室肌细胞L-型钙通道的作用及其信号转导机制

Effect of adrenomedullin on L-type calcium currents and its signaling transduction process in guinea-pig ventricular myocytes

目的 :研究肾上腺髓质素 (adrenomedullin ,ADM)抑制豚鼠心室肌细胞L -型钙通道的信号转导机制。方法 :应用全细胞膜片钳技术 ,记录应用ADM(1- 10 0nmol·L-1)前后L -型钙电流 (ICa ,L) ,以及分别记录应用ADM特异性受体拮抗剂ADM2 2 -52 (10 0nmol·L-1) +ADM(10 0nmol·L-1)、蛋白激酶A (PKA)特异性拮抗剂H - 89(10μmol·L-1) +ADM(10 0nmol·L-1)、蛋白激酶C (PKC)特异性拮抗剂PKC19-3 6(10 μmol·L-1) +ADM(10 0nmol·L-1)、PKC特异性激动剂PMA(1μmol·L-1)前后ICa ,L。结果 :ADM(1- 10 0nmol·L-1)浓度依赖性地抑制豚鼠心室肌细胞ICa ,L,并可被ADM2 2 -52 (10 0nmol·L-1)完全阻断 ;H - 89(10 μmol·L-1)对ADM抑制ICa,L的作用无影响。PKC19-3 6(10μmol·L-1)可完全阻断ADM对ICa ,L的抑制效应 ,且PMA(1μmol·L-1)可模拟ADM对ICa ,L的抑制效应。结论 :ADM作用于特异性ADM受体可浓度依赖性地抑制豚鼠心室肌细胞ICa,L,此作用有可能与PKC激活相关。

AIM: To study the effect of adrenomedullin (ADM) on L-type calcium currents (I Ca,L) and its signaling transduction process in guinea-pig ventricular myocytes. METHODS: By using whole-cell patch clamp technique, the effect of ADM(1-100 nmol·L -1) on I Ca,Lmyocyte. Furthermore, the possible signaling transduction process of ADM on I Ca,L was investigated by observing the effects of ADM 22-52 (a specific ADM-receptor antagonist,100 nmol·L -1)+ADM(100 nmol·L -1), H-89 (a specific protein kinase A inhibitor, 10 μmol·L -1) + ADM(100 nmol·L -1), PKC 19-36 (a specific protein kinase C inhibitor, 10 μmol·L -1) + ADM(100 nmol·L -1) and PMA (a specific protein kinase C activator, 1 μmol·L -1) on I Ca,L, respectively. RESULTS: ADM at the concentrations of 1-100 nmol·L -1 decreased I Ca,L in a dose-dependent manner (P<0.05) and ADM 22-52 completely abolished the ADM-induced inhibition of I Ca,L. H-89 did not attenuate the effects of ADM on I Ca,L. Intracellular application of PKC 19-36 prevented ADM-induced inhibition of I Ca,L, while PMA could mimic the effects of ADM on I Ca,L. CONCLUSION: ADM inhibits I Ca,L, in guinea-pig ventricular myocytes, which is mediated by the specific ADM-receptor and probably related to PKC pathway.