水蛭中枢神经系统神经胶质细胞内的氯离子活性。

Intracellular chloride activity in glial cells of the leech central nervous system.

Ballanyi K, Schlue W R

Institut für Zoologie I, Universität Düsseldorf, FRG.

J Physiol. 1990 Jan;420:325-36. doi: 10.1113/jphysiol.1990.sp017915.

Abstract

Chloride-sensitive double-barrelled microelectrodes were used to measure the intracellular Cl- activity (aicl) and membrane potential (Em) in neuropile glial cells of the leech, Hirudo medicinalis. 2. A close relation between the equilibrium potential for Cl- (ECl = -66.1 +/- 4.9 mV; mean +/- S.D.) and the resting potential (Em = -67.8 +/- 5.2 mV; n = 19) was observed in nominally CO2-HCO3(-)-free, HEPES-buffered solutions. A saline buffered with 2% CO2, 11 mM-HCO3- elicited a membrane hyperpolarization and a concomitant decrease of aCl. 3. Changes in ECl followed these of Em with a lag of less than 30 s in response to various extracellular K+ concentrations [( K+]o) or due to bath-application of carbachol or serotonin. 4. Introduction of a Cl(-)-free solution resulted in a transient depolarization indicating a substantial Cl- conductance and a rapid decrease of aiCl to an apparent value of 0.5-0.9 mM. 5. The loop diuretics furosemide (1 mM) and bumetanide (0.2 mM) did not affect the K(+)-induced changes of aiCl. 6. The results indicate a passive Cl- distribution across the membrane of leech neuropile glial cells as a result of a high Cl- conductance.

摘要

使用对氯离子敏感的双管微电极来测量水蛭（医用水蛭）神经纤维胶质细胞内的氯离子活性（aicl）和膜电位（Em）。2. 在名义上不含二氧化碳 - 碳酸氢根（-）的HEPES缓冲溶液中，观察到氯离子平衡电位（ECl = -66.1 +/- 4.9 mV；平均值 +/- 标准差）与静息电位（Em = -67.8 +/- 5.2 mV；n = 19）之间存在密切关系。用2%二氧化碳、11 mM - 碳酸氢根缓冲的生理盐水引起膜超极化和aCl的伴随降低。3. 响应各种细胞外钾离子浓度[（K + ）o]或由于浴加应用卡巴胆碱或5 - 羟色胺，ECl的变化跟随Em的变化，滞后时间小于30秒。4. 引入无氯离子溶液导致短暂去极化，表明存在大量氯离子电导，并且aiCl迅速降低至0.5 - 0.9 mM的表观值。5. 袢利尿剂速尿（1 mM）和布美他尼（0.2 mM）不影响钾离子诱导的aiCl变化。6. 结果表明，由于高氯离子电导，水蛭神经纤维胶质细胞膜上的氯离子呈被动分布。