Crowe W E, Leader J P
Department of Physiology, University of Otago, Dunedin, New Zealand.
Pflugers Arch. 1994 Jun;427(3-4):210-8. doi: 10.1007/BF00374526.
A technique is described for quantitative epifluorescence studies of the apical membrane of the epithelial cells of the urinary bladder of the toad, Bufo marinus, using the lipid-soluble dye, RH160. When the urinary bladder is appropriately mounted, fluorescence signals, in response to a transepithelial voltage pulse, can be recorded from the epithelium immediately after the addition of the dye to the mucosal bath, and for some hours subsequently. The optical signal, recorded as the change in fluorescence in response to a transepithelial voltage pulse, as a fraction of resting fluorescence, was found to be a linear function of the applied voltage over the range +/- 200 mV, and was approximately 3% for a 100 mV change in transepithelial potential. The signal was enhanced by amiloride (10 mumol.l-1), reduced by bretylium (5 mmol.l-1) and abolished in the presence of nystatin (730 U.ml-1). Calculations based on these data permitted estimation of the fractional resistance of the apical membrane, which was found to be 0.85 under control conditions. Apical membrane resistance was 8.6 k omega.microF, and the basolateral membrane resistance was 1.5 k omega.microF. These findings support the conclusion that the apical membrane of toad urinary bladder epithelial cells is of high resistance, thus resembling other sodium-transporting epithelia.
描述了一种使用脂溶性染料RH160对海蟾蜍（Bufo marinus）膀胱上皮细胞顶端膜进行定量落射荧光研究的技术。当膀胱以适当方式固定时，在将染料添加到黏膜浴中后立即以及随后的几个小时内，可从上皮记录到响应跨上皮电压脉冲的荧光信号。记录为响应跨上皮电压脉冲的荧光变化（作为静息荧光的一部分）的光学信号，在±200 mV范围内被发现是施加电压的线性函数，跨上皮电位变化100 mV时约为3%。该信号被氨氯吡脒（10 μmol·L-1）增强，被溴苄铵（5 mmol·L-1）降低，在制霉菌素（730 U·ml-1）存在时消失。基于这些数据的计算允许估计顶端膜的分数电阻，发现在对照条件下为0.85。顶端膜电阻为8.6 kΩ·μF，基底外侧膜电阻为1.5 kΩ·μF。这些发现支持了海蟾蜍膀胱上皮细胞顶端膜具有高电阻的结论，因此类似于其他钠转运上皮。
