Best L, Miley H E, Yates A P
Department of Medicine and Biological Sciences, University of Manchester, UK.
Exp Physiol. 1996 Nov;81(6):927-33. doi: 10.1113/expphysiol.1996.sp003993.
The perforated patch technique was used to study the effects of hypotonic extracellular solutions on membrane potential and whole-cell currents in intact rat pancreatic beta-cells. A 30% reduction in osmolarity resulted in activation of an outwardly rectifying CI(-)-selective conductance in rat beta-cells. This conductance was inhibited by the anion channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). Exposure to a hypotonic medium also led to a transient stimulation of electrical activity accompanied by cell swelling and a gradual return towards control volume. These effects were also associated with the generation of an inward current at a holding potential of -70mV, and a stimulation of insulin release from intact perifused islets. All of the above effects were inhibited by DIDS. It is suggested that the stimulation of insulin release by hypotonic solutions results from activation of a volume-sensitive anion conductance generating an inward current and leading to a subsequent depolarization of the beta-cell.
采用穿孔膜片钳技术研究低渗细胞外溶液对完整大鼠胰腺β细胞的膜电位和全细胞电流的影响。渗透压降低30%导致大鼠β细胞中一种外向整流性氯离子选择性电导被激活。该电导被阴离子通道阻滞剂4,4'-二异硫氰基芪-2,2'-二磺酸（DIDS）抑制。暴露于低渗介质还导致电活动的短暂刺激，伴有细胞肿胀，并逐渐恢复至对照体积。这些效应还与在-70mV的钳制电位下产生内向电流以及刺激完整灌注胰岛释放胰岛素有关。上述所有效应均被DIDS抑制。提示低渗溶液刺激胰岛素释放是由于激活了一种容积敏感性阴离子电导，产生内向电流并导致β细胞随后去极化。
