Bafilomycin-sensitive acid secretion by mantle epithelium of the freshwater clam, Unio complanatus.
Bafilomycin-sensitive acid secretion by mantle epithelium of the freshwater clam, Unio complanatus.
复制标题
淡水蛤（Unio complanatus）的外套膜上皮分泌巴弗洛霉素敏感的酸。
DOI：
10.1152/ajpregu.1993.264.5.r946
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Hudson,RL
中科院分区：
文献类型：
--
作者：
Hudson,RL
本研究报道了一系列质子易位抑制剂对淡水蛤（Unio complanatus）离体面壳套上皮分泌电原酸的影响。在这种上皮中，腺苷3',5'-环单磷酸腺苷（cAMP）依赖的酸分泌是电致的，当安装在ussing型通量室中时，相当于cAMP依赖的短路电流（Isc）。Bafilomycin A1是液泡型H(+)-ATPases （v型ATPases）的特异性抑制剂，抑制camp依赖性电原酸分泌，IC50为7 nM，在100 nM处效果最大。巴菲霉素A1对酸分泌的抑制作用仅在添加到壳侧时发生，并且通过反复洗涤不会逆转。在巴菲霉素A1抑制camp依赖性Isc的同时，壳面膜上的电位差去极化，根尖膜与基底外膜的电导比降低。双环己基碳二亚胺、己烯雌酚、n -乙基马来酰亚胺和三丁基锡也能抑制camp依赖性Isc和camp依赖性酸的分泌。阿米洛利、奥美拉唑、少霉素、文丘里西丁和瓦巴因对camp依赖性Isc或camp依赖性酸分泌均无影响。无Na（+）或K（+）溶液对camp依赖性Isc和camp依赖性酸分泌没有影响。最后，camp依赖性Isc强烈依赖于壳面室的pH，在pH 6.0时最大camp依赖性Isc被抑制50%，在pH 5.5时完全抑制。（摘要删节250字）
This study reports the effects of a series of putative inhibitors of proton translocation on electrogenic acid secretion by the isolated shell-facing mantle epithelium of the freshwater clam, Unio complanatus. In this epithelium, adenosine 3',5'-cyclic monophosphate (cAMP)-dependent acid secretion is electrogenic and equivalent to the cAMP-dependent short-circuit current (Isc) when mounted in a Ussing-type flux chamber. Bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPases (V-type ATPases), inhibited cAMP-dependent electrogenic acid secretion, with an IC50 of 7 nM and a maximum effect at 100 nM. Inhibition of acid secretion by bafilomycin A1 occurred only when added to the shell side and was not reversed by repeated washings. Concomitant with the inhibition of cAMP-dependent Isc by bafilomycin A1, the electrical potential difference across the shell-facing membrane depolarized, and the conductance ratio of the apical to basolateral membranes decreased. The cAMP-dependent Isc and cAMP-dependent acid secretion also were inhibited by dicyclohexyl-carbodiimide, diethylstilbestrol, N-ethylmaleimide, and tributyltin. Amiloride, omeprazole, oligomycin, venturicidin, and ouabain had no effect on either cAMP-dependent Isc or cAMP-dependent acid secretion. The cAMP-dependent Isc and cAMP-dependent acid secretion were not affected by Na(+)-free or K(+)-free solutions. Finally, the cAMP-dependent Isc was strongly dependent on the pH of the shell-facing compartment, with 50% inhibition of the maximum cAMP-dependent Isc occurring at pH 6.0 and complete inhibition at pH 5.5.(ABSTRACT TRUNCATED AT 250 WORDS)