摘要
目的 观察黄体酮 (Progesterone)对豚鼠结肠平滑肌肌条和细胞的作用 ,借此探讨肠易激综合征 (IBS)的病理生理机制。方法 急性分离豚鼠结肠平滑肌肌条和单个平滑肌细胞。采用TD 112S型等张传感器测量肌条收缩与舒张的幅值、频率 ,并用Axopatch 1 D膜片钳放大器测全细胞模式下的单个平滑肌细胞大电导的钙离子依赖钾通道电流(BKCa)。结果 6 4 8μmol·L-1黄体酮可抑制结肠带肌条的收缩 (0 1792± 0 0 873) g(n =6 ,P <0 0 5 ) ,而低浓度黄体酮仅抑制结肠环行平滑肌肌条的收缩 (16 2pmol·L-10 2 36 0g± 0 15 78g ,n =6 ,P <0 0 5 ;1 6 2nmol·l-10 4 332 g±0 2 111g ,n =6 ,P <0 0 1;3 2 4nmol·l-1部分肌条完全抑制P <0 0 1) ,其效应呈剂量依赖的趋势。细胞实验中 12 96μmol·L-1的黄体酮可抑制BKCa的幅值约 6 0 %± 17% (n =10 ,P <0 0 1) ,而灌流液含 5 μmol·L-1尼卡地平 (nicardip ine)时抑制BKCa的作用不明显。结论 高浓度黄体酮对纵行和环行平滑肌均有抑制作用 ,而低浓度主要抑制环行平滑肌的收缩 ,作用机制与减少细胞外钙离子内流及抑制BKCa有关 ,这种作用可部分解释在临床上IBS妇女患病更普遍的现象 。
AIM To study the effects of progesterone on contractile activity of smooth muscle stripes and the large conduction Ca 2+ activated K + currents (BK Ca ) of single colonic myocytes in female guinea pig proximal colons METHODS Stripes and single cells were separated acutely from guinea pig proximal colon Contractions of stripes were measured by isonic transducer, and Ca 2+ activated K + currents were recorded with an Axopatch 1D amplifier under conventional whole cell patterns RESULTS 64 8 μmol·L -1 progesterone produced longitudinal stripes significantly re laxation(0 1792 g±0 0873 g, n =6, P <0 05) Progesterone resulted in concentration dependent relaxation of circular colonic smooth muscle stripes(162 pmol·L -1 , 0 2360 g±0 1578 g, n =6, P <0 05; 1 62 nmol·L -1 ,0 4332 g±0 2111 g, n =6, P <0 01;3 24 nmol·L -1 ,inhibited completely in several stripes, P <0 01) 12 96 μmol·L -1 progesterone suppressed BK Ca by 60% compared with control ( P <0 01), but failed to inhibit BK Ca in the presence of 5 μmol·L -1 nicardipine. CONCLUSIONS Progesterone at physiological concentration inhibits contractile activity of circular muscles and BK Ca of single circular colonic myocytes by reducing influx of extrocellullar Ca 2+
出处
《中国药理学通报》
CAS
CSCD
北大核心
2003年第9期1043-1047,共5页
Chinese Pharmacological Bulletin
