低渗膨胀增加豚鼠胃窦环行肌细胞钙激活钾电流和延迟整流型钾电流

摘要

目的：观察低渗膨胀对豚鼠胃窦环行肌细胞钙激活rn钾电流和延迟整流型钾电流的影响。方法：采用传rn统全细胞膜片箝技术，对以胶原酶急性分离的单细rn胞进行低渗灌流，观察钾电流的变化。结果：低渗rn灌流液(200 Osmmol/kg)可增加钙激活钾电流和延迟rn整流型钾电流，钙激活钾电流的增加可被四乙基胺rn4 mmol·L-1和Charybdotoxin 200 nmol·L-1完全抑制；rn延迟整流型钾电流的增加可被四乙基胺4 mmol·L-1rn部分抑制，可被4-氨基吡啶10 mmol·L-1完全抑制。rn两种钾电流的增加幅度无显著性差异(P＞0.05)。rn钙激活钾电流在施加低渗灌流(17.0±4.8)s后增rn加；延迟整流型钾电流在(30.7±13.7)s后增加，两rn者的潜伏期存在显著性差异(P＜0.05)。结论：低rn渗膨胀可增加钙激活钾电流和延迟整流型钾电流，rn这种增加效应可能与细胞容积调节有关。%AIM: To observe the effect of hyposmotic swelling on rncalcium-activated potassium current [IK(Ca) ] and delayed rnrectifier potassium current [ IK(V) ] in gastric antral circurnlar myocytes of guinea pig. METHODS: The whole rncell patch-clamp technique was used, and the myocytes rnwere isolated by collagenase. Cells were swelled by the rnhyposmotic solution (200 Osmmol/kg). RESULTS:rnThe hyposmotic solution markedly increased IK(Ca) and rnIK(V). The increase of IK(ca) Was markedly inhibited by rntetrathylammonium (TEA) 4 mmol· L-1 and charybdorntoxin (ChTX) 200 nmol· L-1. The increase of IK(V)rnWas incompletely blocked by TEA and completely rnblocked by 4-aminopyridine (4-AP) 10 mmol·L-1.rnThere was no significant difference between the amplirntudes of the increase of IK(Ca) and IK(V) ( P ＞ 0.05).rnIK(Ca) increased (17.0±4.8) s after the cells were perrnfused with the hyposmotic solution, whereas IK(V) inrncreased (30.7 ± 13.7) s after the cells exposed to the hyrnposmotic solution. There was significant difference berntween the latency of IK(Ca) and IK(V)( P ＜ 0.05).rnCONCLUSION: Hyposmotic swelling increased both rnIK(Ca) and IK(V), and the increment was likely related to rnthe cell volume regulation.