摘要
向胆道加压至 4kPa ,可同时引起血压降低和Oddi括约肌 (SO)肌电活动减弱或消失 ,这总称为胆道加压反射 ,其中前者称为胆道 血压反射 ,后者称为胆道 SO反射。本实验应用 3 2只家兔观察一氧化氮 (NO)对胆道加压反射活动的影响。在静脉滴注去甲肾上腺素 4 μg/(kg·min)引起血压升高和SO肌电振幅增大的基础上 ,再行胆道加压至 4kPa ,仍同时引起血压降低和Oddi括约肌 (SO)肌电活动减弱 ;而在静脉注射NO合酶抑制剂NG 硝基 L 精氨酸 (L NNA) 10mg/kg引起血压升高和SO肌电振幅增大的基础上 ,再行胆道加压至 4kPa,全部动物胆道 血压反射受到完全抑制 ,即未出现血压降低反应 ;少数 ( 3 /8)动物胆道 SO反射受到完全抑制 ,多数 ( 5 /8)动物该反射受到明显抑制 (P <0 0 1)。向SO局部灌注L NNA ,只引起SO肌电振幅增大而不影响血压 ,在此基础上行胆道加压 ,对胆道 SO反射的影响与全身用药相似 ,对胆道 血压反射却无影响。这提示 ,这两种反射活动是相对独立的 ,是经不同传出途径和效应器实现的 ;
In order to elucidate the effect of membrane stretch on ionic currents, we employed the whole cell patch clamp technique to investigate the effects of different kinds of stretch on voltage dependent calcium currents in antrial circular smooth muscle cells of the guinea pig. The membrane stretch induced by superfusing the smooth muscle cells with hyposmotic bath solution enhanced voltage operated calcium current and activated inward holding current. The increase in calcium current occurred within 1 minute of superfusion and the sustained inward holding current was slowly activated after prominent cell swelling. Voltage dependent calcium currents (Ica) were significantly increased by membrane stretch which was induced by cell swelling and cell inflation, but was not affected by direct longitudinal stretch (110～130%) using two electrodes.The results suggest that the cell membrane stretch can increase voltage dependent calcium channel activity and the effect of stretch on calcium channels was related to the membrane tension and/or the direction of membrane stretch.
出处
《生理学报》
CAS
CSCD
北大核心
2000年第1期64-68,共5页
Acta Physiologica Sinica
基金
ThisworkwassupportedbytheNaturalScienceFoundationofHebeiProvinceofChina! (N0 3942 95)
