Guenther E, Schmid S, Hewig B, Kohler K
Department of Pathophysiology of Vision and Neuro-Ophthalmology, University Eye Hospital Tübingen, Germany.
Brain Res. 1996 Apr 29;718(1-2):112-6. doi: 10.1016/0006-8993(96)00077-7.
Angiotensin II (AngII) is one of the most important vasoconstrictive hormones but is also known to act as a neuromodulator in the central nervous system (CNS). Recently, AngII-containing neurons have been identified in the inner nuclear layer and the ganglion cell layer of the retina of various vertebrate species. The present study was undertaken to investigate the physiological effect of AngII on voltage-activated ion channels in retinal ganglion cells of the rat, Ion currents were recorded in freshly dissociated cells in the whole-cell configuration of the patch-clamp technique. AngII concentrations of 1 to 100 microM had no effect on sodium currents but modulated the influx through high voltage-activated (HVA) calcium channels in a 2-fold manner. AngII (100 microM) increased the HVA-calcium current by 15 to 65% in 41% of the cells, whereas a current reduction of 18 to 69% was observed in 59% of the cells. AngII effects were reversible within a few seconds of reperfusion with bath solution. Calcium-current kinetics and current-voltage relations remained unaffected.
血管紧张素II（AngII）是最重要的血管收缩激素之一，但也被认为是中枢神经系统（CNS）中的一种神经调节剂。最近，在各种脊椎动物的视网膜内核层和神经节细胞层中发现了含AngII的神经元。本研究旨在探讨AngII对大鼠视网膜神经节细胞电压激活离子通道的生理作用，采用膜片钳技术的全细胞模式记录新鲜分离细胞中的离子电流。1至100微摩尔的AngII浓度对钠电流无影响，但以两倍的方式调节通过高电压激活（HVA）钙通道的内流。在41%的细胞中，100微摩尔的AngII使HVA钙电流增加了15%至65%，而在59%的细胞中观察到电流减少了18%至69%。在用浴液再灌注几秒钟内，AngII的作用是可逆的。钙电流动力学和电流-电压关系不受影响。
