Regulated Cl transport, K and Cl permeability, and exocytosis in T84 cells.
Regulated Cl transport, K and Cl permeability, and exocytosis in T84 cells.
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调节 T84 细胞中的 Cl 转运、K 和 Cl 通透性以及胞吐作用。
DOI：
10.1172/jci117181
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Machen,TE
中科院分区：
文献类型：
--
作者：
Huflejt,ME;Blum,RA;Miller,SG;Moore,HP;Machen,TE
我们测量了与T84单层细胞中Cl分泌增加（即短路电流，ISC，以微a /cm2计）和顶端（ap） Cl渗透性（PCl）和基底侧（bl） K渗透性（PK）（均以cm/s计）相关的兴奋剂诱导的胞外分泌变化。用制霉菌素渗透bl或ap膜，测定PCl和PK。用荧光染料6-甲氧基- n -（3-磺丙基）喹啉（SPQ）测定PCl。采用一种无创、灵敏的方法（释放35so4标记的糖胺聚糖[GAG]，一种高尔基衍生囊泡的液相标记物）来测量ap和bl膜上的胞吐。静息时，ISC = 3.6, PK = 0.8 × 10(-6)，电激电位下PCl = 2.1 × 10(-6)，电激电位下PCl = 2.4 × 10(-6)， ap侧和bl侧均有组成性GAG分泌（即胞吐）（bl侧和bl侧）。碳醇(C)增加：ISC (δ = 18.6)， PK（6.5倍），PCl（1.8-2.9倍），以及ap（2.2-3.5倍）和bl（2.0-3.0倍）膜的胞吐。福斯克林(F)增加ISC （δ = 29）、PCl （δ = 5.5-11x）和ap胞吐（δ = 1.5-2x），但对PK和bl胞吐无影响。当将C添加到F处理的细胞中时，对ISC会产生协同效应，反之则不会，尽管F+C对PCl、PK和/或GAG分泌的特征性影响与单独添加兴奋剂时相同。Cl的分泌是由ap和bl膜通道的协同激活引起的，胞吐可能在这些事件中起作用。图片
We measured stimulant-induced changes of exocytosis that are associated with increases in Cl secretion (i.e., short circuit current, ISC, in microA/cm2) and apical (ap) Cl permeability (PCl) and basolateral (bl) K permeability (PK) (both in cm/s) in T84 monolayers. PCl and PK were measured by permeabilizing the bl or ap membrane with nystatin. PCl was also measured with a fluorescent dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). A noninvasive and sensitive method (release of 35SO4-labeled glycosaminoglycan [GAG], a fluid-phase marker of Golgi-derived vesicles) was used to measure exocytosis at both ap and bl membranes. At rest, ISC = 3.6, PK = 0.8 x 10(-6), PCl = 2.1 x 10(-6) with SPQ and 2.4 x 10(-6) electrically, and there was constitutive GAG secretion (i.e., exocytosis) to both ap and bl sides (bl > 2 x ap). Carbachol (C) increased: ISC (delta = 18.6), PK (6.5x), PCl (1.8-2.9x), and exocytosis to both ap (2.2-3.5x) and bl (2.0-3.0x) membranes. Forskolin (F) increased ISC (delta = 29), PCl (5.5-11x) and ap exocytosis (1.5-2x), but had no effect on PK or bl exocytosis. Synergistic effects on ISC occurred when C was added to F-treated cells but not vice versa, even though the characteristic effects of F+C on PCl, PK, and/or GAG secretion were identical to those exhibited when stimulants were added individually. Cl secretion results from coordinated activation of channels at ap and bl membranes, and exocytosis may play a role in these events.Images