Nilius B, Prenen J, Droogmans G
KU Leuven, Laboratorium voor Fysiologie, Campus Gasthuisberg, B-3000 Leuven, Belgium.
Pflugers Arch. 1998 Oct;436(5):742-8. doi: 10.1007/s004240050697.
We have studied the modulation of the volume-regulated anion channel (VRAC) in cultured endothelial cells from bovine pulmonary artery (CPAE cells) by extra- and intracellular pH. The patch-clamp technique was used in combination with a fluorimetric measurement of intracellular pH using BCECF. Swelling of CPAE cells was accompanied by a slow acidification. The metabolites lactate and HCO3- both permeate through VRAC. The inactivation of VRAC currents at positive potentials is accelerated at a decreased extracellular pH and decelerated at alkaline pH. The instantaneous current amplitude is only slightly affected. Intracellular alkalization reduced whereas acidification enhanced the currents flowing through VRAC at all potentials. HCO3- and lactate permeation, as well as the up-regulation of VRAC at an acidic intracellular pH might be related to a possible role of this channel in cellular pH regulation.
我们研究了细胞外和细胞内pH对牛肺动脉培养内皮细胞（CPAE细胞）中容积调节性阴离子通道（VRAC）的调节作用。采用膜片钳技术，并结合使用BCECF对细胞内pH进行荧光测量。CPAE细胞肿胀伴随着缓慢的酸化过程。代谢产物乳酸和HCO₃⁻均可通过VRAC渗透。在正电位下，VRAC电流的失活在细胞外pH降低时加速，在碱性pH时减速。瞬时电流幅度仅受到轻微影响。细胞内碱化会降低，而酸化会增强在所有电位下流经VRAC的电流。HCO₃⁻和乳酸的渗透，以及在酸性细胞内pH下VRAC的上调可能与该通道在细胞pH调节中的潜在作用有关。
