Pedersen P S
Department of Pediatrics, Rigshospitalet Copenhagen, Denmark.
Exp Physiol. 1992 Nov;77(6):863-71. doi: 10.1113/expphysiol.1992.sp003653.
Transepithelial short-circuit current (Iscc) and intracellular free Ca2+ (Ca2+i) was studied in monolayers of cultured human sweat duct cells (CSDCs) in the presence or absence of HCO3- (and CO2) in the bathing solutions. Addition of HCO3- (and CO2) increased the control Iscc by more than 50%. The effect of HCO3- (and CO2) on Iscc was confined to the serosal bath. The HCO3- (and CO2) effect was also studied during stimulation with the cholinergic agonist methacholine (MCh), which in CSDC induces a complex response consisting of an initial Iscc and Ca2+i spike, which is independent of extracellular Ca2+, followed by regular Iscc and Ca2+i oscillations, which are absent during Ca(2+)-free bathing conditions. The sustained Iscc and Ca2+i oscillations, but not the initial Iscc and Ca2+i spike were abolished by the removal of extracellular HCO3- (and CO2). It is concluded that the Ca2+ influx and the Iscc in CSDCs are critically influenced by the presence of extracellular HCO3- (and CO2) in the bathing solutions.
在存在或不存在 HCO3-（以及 CO2）的情况下，研究了培养的人汗腺导管细胞（CSDCs）单层中的跨上皮短路电流（Iscc）和细胞内游离 Ca2+（Ca2+i）。添加 HCO3-（以及 CO2）使对照 Iscc 增加了 50%以上。HCO3-（以及 CO2）对 Iscc 的影响仅限于浆膜浴。还研究了在胆碱能激动剂乙酰甲胆碱（MCh）刺激期间 HCO3-（以及 CO2）的作用，在 CSDCs 中，MCh 诱导出一种复杂反应，包括最初的 Iscc 和 Ca2+i 尖峰，这与细胞外 Ca2+无关，随后是规则的 Iscc 和 Ca2+i 振荡，在无 Ca2+的浴液条件下不存在这种振荡。去除细胞外 HCO3-（以及 CO2）可消除持续的 Iscc 和 Ca2+i 振荡，但不会消除最初的 Iscc 和 Ca2+i 尖峰。得出的结论是，CSDCs 中的 Ca2+内流和 Iscc 受到浴液中细胞外 HCO3-（以及 CO2）的显著影响。
