血管紧张素Ⅱ增加新生鼠脑细胞胞浆Ca^(2+)浓度

Angiotensin Ⅱ Increases Intracellular Calcium Concentration ([Ca^(2+)]_i) in Neonatal Rat Brain Cells

本文应用荧光钙测定技术观察了血管紧张素Ⅱ(AⅡ)对新生Wistar鼠脑细胞胞浆Ca^(2+)浓度([Ca^(2+)]_i)的影响。结果表明:血管紧张素Ⅱ在1nmol/L—1μmol/L浓度下可诱导新生鼠脑细胞[Ca^(2+)]_i增加,具量效关系。在无外Ca^(2+)存在对,其增加幅度有所减少。上述效应可被血管紧张素Ⅱ拮抗剂Saralasin所阻断,并呈剂量依赖关系。上述结果提示,血管紧张素Ⅱ可激活血管紧张素AⅡ受体,增加脑细胞[Ca^(2+)]_i,该效应通过细胞内Ca^(2+)释放和细胞外Ca^(2+)内流两条适径实现,前者的作用是主要的。

Fluorosent calcium assay technique was used to investigate the effects of angiotensin Ⅱ (A Ⅱ ) on the intracellular calcium concentration ([Ca^(2+)_1) in neonatal rat brain cells in vitro. AⅡ dose-dependently increased the concentration of intracellular calcium (P<0.01).The effects of AⅡ remained in Ca^(2+)-free medium, although the degree of increase was less obvious than that in the presence of Ca^(2+)(p<0.01). The effect of AⅡ was antagonized dose-dependently by the AⅡ antagonist saralasin, suggesting that this effect was an AⅡ receptor-mediated event. These results indicate that AⅡ increases [Ca^(2+)]_1 through two mechanisms, i.e. the release from intracellular Ca^(2+) storage and the influx of extracellular Ca^(2+), with the former playing a more important role.