Lobo M V, Marusic E T
Am J Physiol. 1986 Feb;250(2 Pt 1):E125-30. doi: 10.1152/ajpendo.1986.250.2.E125.
Angiotensin II stimulus on perifused bovine adrenal glomerulosa cells elicited an increase in 86Rb efflux from cells previously equilibrated with the radioisotope. When 45Ca fluxes were measured under similar conditions, it was observed that Ca and Rb effluxes occurred within the first 30 s of the addition of the hormone and were independent of the presence of external Ca. The 86Rb efflux due to angiotensin II was inhibited by quinine and apamin. The hypothesis that the angiotensin II response is a consequence of an increase in the K permeability of the glomerulosa cell membrane triggered by an increase in cytosolic Ca is supported by the finding that the divalent cation ionophore A23187 also initiated 86Rb or K loss (as measured by an external K electrode). This increased K conductance was also seen with 10(-4) M ATP. Quinine and apamin greatly reduced the effect of ATP or A23187 on 86Rb or K release in adrenal glomerulosa cells. The results suggest that Ca-dependent K channels or carriers are present in the membranes of bovine adrenal glomerulosa cells and are sensitive to hormonal stimulus.
对经放射性同位素预平衡的灌流牛肾上腺球状带细胞施加血管紧张素II刺激，会使细胞的86Rb外流增加。在相似条件下测量45Ca通量时，观察到在添加激素后的最初30秒内会出现Ca和Rb外流，且与细胞外Ca的存在无关。血管紧张素II引起的86Rb外流受到奎宁和蜂毒明肽的抑制。有研究发现二价阳离子载体A23187也会引发86Rb或K外流（通过外部K电极测量），这支持了以下假说：血管紧张素II反应是由细胞溶质Ca增加触发的球状带细胞膜K通透性增加的结果。10(-4) M ATP也会出现这种K电导增加的情况。奎宁和蜂毒明肽大大降低了ATP或A23187对肾上腺球状带细胞86Rb或K释放的影响。结果表明，Ca依赖性K通道或载体存在于牛肾上腺球状带细胞的膜中，且对激素刺激敏感。
