Rose R C, Nahrwold D L
J Membr Biol. 1976 Oct 20;29(1-2):1-22. doi: 10.1007/BF01868949.
Ion transport and electrical properties of rabbit and guinea pig gallbladders were investigated to gain further information about the active transport mechanism that mediates fluid absorption. The intracellular and transepithelial electrical potentials were measured simultaneously using the microelectrode technique. Exposure of the mucosal surface to Amphotericin B resulted in the prompt development of a serosa-positive electrical potential difference (PD) which could not be attributed to an alteration in ion diffusion potentials across either the cell membrane or across the tight junction. Because the Amphotericin B-induced PD was immediately dependent on warm temperatures and O2, and was independent of NA and K concentration gradients across the cell membrane, it is suggested that active ion transport is directly responsible for the PD. Since the PD was abolished in the absence of Na in the bathing solutions, a rheogenic Na pump is postulated; this pump also appears to be operative in tissues not exposed to Amphotericin B. The specific tissue properties altered by Amphotericin B to produce a serosa-positive PD remain incompletely defined. The results of the present study indicate that ion transport by rabbit gallbladder in vitro is a consequence of a rheogenic active Na transport mechanism at the basolateral membranes which, in conjunction with a coupled NaC1 influx process at the mucosal border, ultimately results in absorption of NaC1 and water.
对兔和豚鼠胆囊的离子转运和电特性进行了研究，以获取更多有关介导液体吸收的主动转运机制的信息。使用微电极技术同时测量细胞内和跨上皮的电势。将黏膜表面暴露于两性霉素B会导致迅速产生浆膜阳性电势差（PD），这不能归因于跨细胞膜或紧密连接的离子扩散电位的改变。由于两性霉素B诱导的PD立即依赖于温暖的温度和氧气，并且独立于跨细胞膜的钠和钾浓度梯度，因此表明主动离子转运直接导致了该PD。由于在浴液中没有钠的情况下PD消失，因此推测存在生电钠泵；这种泵似乎在未暴露于两性霉素B的组织中也起作用。两性霉素B改变以产生浆膜阳性PD的特定组织特性仍未完全明确。本研究结果表明，兔胆囊体外的离子转运是基底外侧膜上生电主动钠转运机制的结果，该机制与黏膜边界处的耦合氯化钠流入过程相结合，最终导致氯化钠和水的吸收。
