CAJ | 학술논문

目的探讨硫化氢(H2S)对大鼠结肠收缩活动的影响及其离子通道机制.方法取30只雄性Wistar大鼠远端结肠制备纵行肌条(LMS)及环形肌条(CMS);张力换能器及多通道生理信号采集处理系统记录H2S供体硫氢化钠(NaHS)对LMS和CMS自发性收缩活动的影响及河豚毒素(TTX)孵育后NaHS对LMS和CMS收缩活动的影响;采用酶消化法分离近端结肠平滑肌细胞,运用全细胞膜片钳技术记录NaHS对平滑肌细胞L型钙通道电流(ICa.L)和大电导钙激活钾电流(IBKCa)的影响.结果 NaHS[(1～ 12)× 10-5mol/L]浓度依赖性促进结肠LMS和CMS的收缩活动,其中(2 ～ 12)×10-5mol/L NaHS使LMS和CMS收缩显著增加(均P＜0.05),且该促进作用不被TTX阻断;NaHS(6 ×10-5和12×10-5 mol/L)浓度依赖性促进ICa.L,使0 mV处ICa,L由(-3.16 ±0.47)pA/pF分别增加至(-3.33 ±0.54)、(-3.65±0.66)pA/pF(均P＜0.05);NaHS(12×10-5 mol/L)作用前后,最大峰电流均在0 mV处,不改变L型钙通道的电压依赖特性,亦不影响L型钙通道的激活态;NaHS(12×10-5 mol/L)对L型钙通道的促进作用具有时间依赖性、可逆性;NaHS(6×10-5和12×10-5 mol/L)浓度依赖性抑制IBKCa,使60 mV处IBKCa由(16.68±1.23) pA/pF分别降低至(15.26±2.67)、(13.80±3.04)pA/pF(均P＜0.05).结论低浓度H2S可能通过开放平滑肌细胞L型钙通道,抑制大电导钙激活钾通道,进而促进大鼠结肠平滑肌收缩.
목적 탐토류화경(H2S)대대서결장수축활동적영향급기리자통도궤제.방법 취30지웅성Wistar대서원단결장제비종행기조(LMS)급배형기조(CMS);장력환능기급다통도생리신호채집처리계통기록H2S공체류경화납(NaHS)대LMS화CMS자발성수축활동적영향급하돈독소(TTX)부육후NaHS대LMS화CMS수축활동적영향;채용매소화법분리근단결장평활기세포,운용전세포막편겸기술기록NaHS대평활기세포L형개통도전류(ICa.L)화대전도개격활갑전류(IBKCa)적영향.결과 NaHS[(1～ 12)× 10-5mol/L]농도의뢰성촉진결장LMS화CMS적수축활동,기중(2 ～ 12)×10-5mol/L NaHS사LMS화CMS수축현저증가(균P＜0.05),차해촉진작용불피TTX조단;NaHS(6 ×10-5화12×10-5 mol/L)농도의뢰성촉진ICa.L,사0 mV처ICa,L유(-3.16 ±0.47)pA/pF분별증가지(-3.33 ±0.54)、(-3.65±0.66)pA/pF(균P＜0.05);NaHS(12×10-5 mol/L)작용전후,최대봉전류균재0 mV처,불개변L형개통도적전압의뢰특성,역불영향L형개통도적격활태;NaHS(12×10-5 mol/L)대L형개통도적촉진작용구유시간의뢰성、가역성;NaHS(6×10-5화12×10-5 mol/L)농도의뢰성억제IBKCa,사60 mV처IBKCa유(16.68±1.23) pA/pF분별강저지(15.26±2.67)、(13.80±3.04)pA/pF(균P＜0.05).결론 저농도H2S가능통과개방평활기세포L형개통도,억제대전도개격활갑통도,진이촉진대서결장평활기수축.
Objective To explore the effects of hydrogen sulfide (H2S) on colonic contraction of rats at low concentration and ion channel mechanisms.Methods Organ bath recordings were used to examine the contraction of colonic smooth muscle strips.The whole-cell patch-clamp technique was used to record the currents of L-type calcium and large conductance Ca2+-activated K+ (BKCa) channels in smooth muscle cells isolated from 30 male Wistar rats.Results The H2S donor NaHS ((1-12) × 10-5mol/L) increased the spontaneous contractions of longitudinal and circular muscle strips in a dose-dependent manner (all P ＜0.05) and the effect could not be blocked by tetrodotoxin.NaHS (6 × 10-5 and 12 × 10-5 mol/L) reversibly increased the L-type calcium current (ICa,L) in a dose-dependent manner.And the peak of ICa,L at 0 mV increased from (-3.16 ± 0.47) to (-3.33 ± 0.54) and (-3.65 ± 0.66) pA/pF respectively (n =6,both P ＜ 0.05).Current-voltage (Ⅰ-Ⅴ) curve had no shift after NaHS treatment and H2S donor caused no change in the curves of steady-state activation.Likewise BKCa channel was significantly inhibited by NaHS (6 × 10-5 and 12 × 10-5 mol/L) in a dose-dependent manner.And IBKCa at 60 mV decreased from (16.68 ± 1.23) to (15.26 ± 2.67) and (13.80 ± 3.04) pA/pF respectively (both P ＜ 0.05).Conclusions H2S at low concentrations increases the spontaneous contraction of rat colonic smooth muscle in a dose-dependent manner.Such an effect may be due to a direct activation of L-type calcium channel and an inhibition of BKCa channel in smooth muscle cells.