Effects of calcium antagonist TMB-8 on active Na and Cl transport in rabbit ileum.
Effects of calcium antagonist TMB-8 on active Na and Cl transport in rabbit ileum.
复制标题
钙拮抗剂 TMB-8 对兔回肠活性 Na 和 Cl 转运的影响。
DOI：
10.1152/ajpgi.1986.250.5.g691
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Sharp,GW
中科院分区：
文献类型：
--
作者：
Donowitz,M;Cusolito,S;Sharp,GW
在基础条件下和通过增加细胞内cAMP含量或通过暴露于两种通过改变细胞内Ca ~（2+）起作用的激动剂（卡巴胆碱和5-羟色胺）改变转运后，研究了3，4，5-三甲氧基苯甲酸8-（N，N-二乙基氨基）辛酯（TMB-8）（一种在细胞内储存内捕获钙的药物）对家兔回肠主动电解质转运的影响。TMB-8降低回肠短路电流，并通过增加粘膜至血清的Na和Cl通量来增加活性Na和Cl吸收。这些影响被逆转，通过增加浴溶液中的钙2+到4 mM，浓度本身并不改变基底回肠运输。葡萄糖和氨基酸（丙氨酸）诱导的回肠中Na吸收的最大增加不受TMB-8的影响。对TMB-8基础转运的影响与回肠浆膜表面45 Ca 2+进入的变化无关。TMB-8不改变cAMP诱导的分泌，这是因为它对8-溴-cAMP（10（-4）M）引起的短路电流增加没有影响。TMB-8完全阻止卡巴胆碱的转运作用，但不抑制5-羟色胺的作用。这些数据表明细胞内Ca 2+在调节基础回肠Na和Cl转运中的作用，但不在cAMP诱导的分泌中。似乎有几个池的细胞内Ca 2+参与神经体液作用的主动电解质转运。
The effects of 3,4,5-trimethoxybenzoate 8-(N,N-diethylamino)octyl ester (TMB-8), an agent that traps calcium within intracellular stores, were studied on active electrolyte transport in rabbit ileum under basal conditions and after altering transport by increasing the intracellular cAMP content or by exposure to two agonists that act by altering intracellular Ca2+ (carbachol and serotonin). TMB-8 decreased the ileal short-circuit current and increased active Na and Cl absorption by increasing the mucosal-to-serosal Na and Cl fluxes. These effects were reversed by increasing the bathing solution Ca2+ to 4 mM, a concentration that itself did not alter basal ileal transport. The maximum glucose- and amino acid (alanine)-induced increase in Na absorption in the ileum was not affected by TMB-8. The effects on basal transport of TMB-8 were not associated with a change in 45Ca2+ entry across the ileal serosal surface. TMB-8 did not alter cAMP-induced secretion, as judged by its lack of effect on the increase in short-circuit current caused by 8-bromo-cAMP (10(-4) M). TMB-8 totally prevented the transport effects of carbachol but did not inhibit the effects of serotonin. These data suggest a role for intracellular Ca2+ in regulation of basal ileal Na and Cl transport but not in cAMP-induced secretion. There appear to be several pools of intracellular Ca2+ involved in neurohumoral effects on active electrolyte transport.