Site and mode of adrenaline action on chloride transport across the rabbit corneal epithelium.
Site and mode of adrenaline action on chloride transport across the rabbit corneal epithelium.
复制标题
肾上腺素对穿过兔角膜上皮的氯化物转运的作用部位和方式。
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
R. Wong
中科院分区：
文献类型：
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作者：
S. Klyce;R. Wong
1.用微电极技术研究了肾上腺素刺激下兔角膜上皮细胞氯分泌的膜事件。2.脉冲肾上腺素(5×10~(-10)M终浓度)作用于上皮细胞的两侧，可引起鳞状细胞外膜上皮阻力的一过性降低。这一反应是可逆的，并可被SO4完全取代的氯离子完全阻断。3.肾上腺素一般引起鳞状细胞外膜上皮细胞电位的小幅瞬时升高。肾上腺素反应的逆转电位，角膜电位为45-1 mV，外膜为22-8 mV。4.在无氯溶液中浸泡泪侧时，肾上腺素总是超极化。反转梯度(间质侧无氯)缓慢而持续地改变对去极化的反应，在2小时后达到稳定水平。5.外膜对肾上腺素反应的翻转电位在较宽的范围内是泪侧氯浓度的半对数函数，斜率为56 mV/ten。在撕裂侧氯浓度为41-5 mM时，反转电位为零，该值可被认为代表细胞氯浓度。6.在两侧组织灌流无氯溶液以消除肾上腺素反应后，将氯重新注入基质侧可恢复超极化方向上皮细胞的电位反应。哇巴因(10(-5)M)抑制反应的恢复。7.结果支持肾上腺素对上皮细胞阴离子转运的影响模型：CL是通过与Na-k激活的ATPase相连的活性过程，逆着电化学电位梯度从基质侧转运到细胞内的。正常情况下，从细胞到泪水之间存在一个轻微的梯度，有利于氯的被动向外扩散。后一个过程被肾上腺素增强，肾上腺素增加细胞环磷酸腺苷，进而增加细胞外膜被动氯的通透性。
1. Membrane events accompanying adrenaline‐stimulated Cl secretion by the isolated rabbit corneal epithelium were investigated with micro‐electrodes. 2. Pulses of adrenaline (5 X 10(‐10) M final concentration) delivered to either side of the epithelium produced a transient decrease in epithelial resistance occuring at the outer membrane of the squamous cell. This response was reversible and could be blocked completely by total Cl substitution with SO4. 3. Adrenaline generally produced a small transient increase in epithelial potential occuring also at the squamous cell outer membrane. Reversal potentials obtained for the adrenaline response were 45‐1 mV for corneal potential and 22‐8 mV for outer membrane. 4. Adrenaline always hyperpolarized epithelial potential when the tear side was bathed in Cl‐free solution. Reversing the gradient (Cl‐free on the stromal side) slowly and consistently changed the response to a depolarization which reached a steady level after 2 hr. 5. The reversal potential of the outer membrane for the adrenaline response was found to be a semilogarithmic function of the tear side Cl concentration over a broad range with a slope of 56 mV/decade. The reversal potential was zero at a tear side Cl concentration of 41‐5 mM, which value may be taken to be representative of cell Cl concentration. 6. After abolishing the adrenaline response by perfusing both sides of the tissue with Cl‐free solution, reintroduction of Cl to the stromal side led to a recovery of the epithelial potential response in the hyperpolarizing direction. The recovery of the response was inhibited by ouabain (10(‐5) M). 7. The results supported the following model for the influence of adrenaline on anion transport in the epithelium: Cl is transported against an electrochemical potential gradient into the cells from the stromal side by an active process linked to Na‐k activated ATPase. Normally a slight gradient exists from cells to tears favouring the passive outward diffusion of Cl. This latter process is enhanged by adrenaline, which increases cell cyclic AMP, in turn increasing the passive Cl permeability of the outer cellular membrane.