Ehrenspeck G
Biochim Biophys Acta. 1982 Jan 22;684(2):219-27. doi: 10.1016/0005-2736(82)90009-8.
Ouabain-treated turtle bladders bathed on both surfaces by identical HCO3-/CO2-containing, Cl- -free Na+ media exhibit a short-circuit current (Isc) and transepithelial potential (p.d.) serosa electronegative to mucosa. Addition of 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of cyclic nucleotide phosphodiesterase, rapidly reverses the direction of the Isc and p.d. The IBMX-induced reversal of Isc and p.d. is (1) dependent on the presence of HCO3- (and CO2) in the serosal bathing fluid, (2) independent of Na+ and other ions in the bathing medium, (3) decreased by inhibitors of carbonic anhydrase or oxidative metabolism, (4) increased by the serosal addition of cyclic AMP or the disulfonic stilbene, SITS. The results constitute evidence that the reversed Isc elicited by IBMX represents electrogenic secretion of HCO3-.
哇巴因处理过的海龟膀胱，其两面均浸泡在含有相同的HCO₃⁻/CO₂且不含Cl⁻的Na⁺介质中，会表现出短路电流（Isc）和跨上皮电位（p.d.），浆膜对粘膜呈电负性。添加3-异丁基-1-甲基黄嘌呤（IBMX），一种环核苷酸磷酸二酯酶的抑制剂，会迅速使Isc和p.d.的方向逆转。IBMX诱导的Isc和p.d.的逆转（1）依赖于浆膜浴液中HCO₃⁻（和CO₂）的存在，（2）与浴液中的Na⁺和其他离子无关，（3）被碳酸酐酶抑制剂或氧化代谢抑制剂降低，（4）通过向浆膜添加环磷酸腺苷或二磺酸芪（SITS）而增加。这些结果证明，IBMX引发的逆转Isc代表了HCO₃⁻的电分泌。
