Stimulation of acid formation in permeable gastric glands by valinomycin.
Stimulation of acid formation in permeable gastric glands by valinomycin.
复制标题
缬氨霉素刺激可渗透性胃腺中的酸形成。
DOI：
10.1152/ajpgi.1988.255.3.g313
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Steiner,L
中科院分区：
文献类型：
--
作者：
Hersey,SJ;Steiner,L
用洋地黄素处理使胃腺通透性增强，以研究胃酸形成的离子需求。酸的形成是通过一种新的弱碱探针[14C]苄胺的积累来监测的。依赖于ATP的酸的形成需要K+浓度依赖的方式，表观K0.5=7 mM。酸形成的阴离子依赖性给出了氯离子=I大于溴离子大于硝酸根大于SO4=异硫酸盐的选择性顺序，其中异硫酸根的效率约为氯离子的50%。酸形成对[Cl]的依赖关系给出表观K0.5=6 mm。在静息腺体中加入K+离子载体伐林霉素(西咪替丁预处理)，可使依赖于ATP的酸性物质的形成增加两到三倍。相比之下，受刺激的腺体(Forsklin预处理)显示出更多的苯胺与三磷酸腺苷的积聚，但显著地减少了对呋喃霉素的刺激。对呋喃霉素的刺激既需要K+，也需要Cl-，可被奥美拉唑和SCH 28080所抑制。结果表明，从静止状态向刺激状态转变的主要事件包括壁细胞分泌膜K+和阴离子通透性的变化。
Isolated gastric glands made permeable with digitonin treatment were employed to study the ionic requirements of acid formation. Acid formation was monitored by the accumulation of a novel weak base probe, [14C]benzylamine. ATP-dependent acid formation was found to require K+ in a concentration-dependent manner, with an apparent K0.5 = 7 mM. The anion dependence of acid formation gave a selectivity sequence of Cl = I greater than Br greater than NO3 greater than SO4 = isethionate, with isethionate being approximately 50% as effective as Cl. The dependence of acid formation on [Cl] gave an apparent K0.5 = 6 mM. Addition of the K+ ionophore, valinomycin, to resting glands (cimetidine pretreatment) resulted in a two- to threefold increase in ATP-dependent acid formation. In contrast, stimulated (forskolin pretreated) glands showed a greater accumulation of benzylamine with ATP but significantly less valinomycin stimulation. The valinomycin stimulation required both K+ and Cl- and was inhibited by omeprazole and Sch 28080. The results are interpreted to indicate that major events in the transition from a resting to a stimulated state include changes in both K+ and anion permeability of the secretory membrane of parietal cells.