Effect of beta-adrenergic agents on intracellular potential of rabbit ciliary epithelium.
Effect of beta-adrenergic agents on intracellular potential of rabbit ciliary epithelium.
复制标题
β-肾上腺素能药物对兔睫状上皮细胞内电位的影响。
DOI：
10.1076/ceyr.17.1.24.5258
复制
发表时间：
1998
影响因子：
2
通讯作者：
Krupin,T
中科院分区：
文献类型：
--
作者：
Tang,LQ;Hong,PH;Siddiqui,Y;Sarkissian,ES;Huang,RY;Lee,E;Krupin,T
PURPOSETo study the effects of ß-adrenergic agents on intra-cellular potential (Vm) of the isolated and intact rabbit ciliary epithelium.METHODSVm was measured on the isolated intact ciliary epithelium superfused with adrenergic agents and cyclic AMP modulators.RESULTSThe nonselective ß-adrenergic agonist isoproterenol depolarized Vm in a dose-dependent fashion. ß-adrenergic antagonists alone had no effect on baseline Vm. The isoproterenol response was blocked by the nonselective antagonist timolol (5 × 10 -5 M). The selective ß 2 -antagonist ICI 118-551 caused a greater inhibition (IC 50 ~7 × 10 -7) than the selective ß 1 -antagonist betaxolol (IC 50 ~6 × 10 -6) . The isoproterenol response was also significantly (p < 0.03) blocked by the non-selective a-antagonist phentolamine. Cyclic AMP and phosphodiesterase inhibitors significantly decreased Vm. Pretreatment with these inhibitors potentiated the agonist-induced depolarization. Barium, a blocker of Ca 2+ -sensitive K + channels, significantly decreased baseline Vm. Barium pretreatment blocked the ß-agonist and cAMP induced depolarization of Vm, suggesting that the K + current is necessary for the observed isoproterenol response. Pretreatment with the cotransport inhibitor bumetanide had no effect on the isoproterenol-induced response.CONCLUSIONSThe ß-adrenergic agonist isoproterenol affects ionic transport processes across the ciliary epithelium (b 2 > b 1) . This effect is likely mediated through adenylate cyclase coupled to adrenoreceptors and requires the presence of the K + current. Blockage of the isoproterenol-induced decrease in Vm by a nonselective a-adrenergic antagonist indicates an interaction between the two adrenergic systems in the ciliary epithelium.
