摘要
目的 :研究多巴胺对血管平滑肌细胞大电流、钙激活钾 (BKca)通道的影响及其信息传递机制。方法 :用膜片钳细胞贴附式技术 ,记录细胞孵育液内灌流多巴胺受体激动剂、阻断剂以及第二信使及相关蛋白激酶拮抗剂对猪冠状动脉血管平滑肌细胞BKca通道活动的影响。结果 :多巴胺增加BKca通道活性 (P <0 .0 1 ) ;并可被DA 1受体阻断剂SCH2 3390完全阻断 ,但不受β2 受体阻断剂普萘洛尔的影响。腺苷酸环化酶抑制剂SQ2 2 5 36可完全阻断多巴胺的作用 ;而cAMP拟似剂CTP cAMP单独应用可增强BKCa通道的活性。蛋白激酶A的拮抗剂RP 8CTP cAMPs对多巴胺增强BKCa活性作用无影响。而蛋白激酶G的拮抗剂KT5 82 3完全阻断了多巴胺这一效应 (P <0 .0 1 )。结论 :多巴胺作用于DA 1受体增强猪冠状动脉血管平滑肌的BKCa活性是通过升高cAMP激活PKG引起的。
Aim:To study the effects of dopamine on the large conductance, calcium and voltage activated potassium (BK Ca ) channel in porcine coronary vascular smooth muscle cells and the mechanism of the signal transduction process. Methods:With patch clamp technique,in cell attached patches, the activity of the BK Ca channel in porcine coronary vascular smooth muscle cells were recorded,after pre treating the cells with the agonists and antagonists of DA-1 receptor, β 2 receptor,cAMP,PKA or PKG respectively.Results:Treating coronary myocytes with dopamine enhanced channel activity( P <0.01),which was completely prevented by pretreating the cells with SCH23390,but not by proprandol.The activity of BK Ca channels induced by dopamine was blocked by SQ22536,and application of CPT cyclic AMP increased channel activity substantially. Exposure of cells to RP 8CPT cAMPs had no effect on dopamine induced channel activity, in another set of cell attached experiments the stimulatory effect of dopamine was reversed by subsequent addition of KT5823. Conclusion: Activation of DA 1 receptors by dopamine causes stimulation of BK Ca channel which is dependent upon cyclic AMP induced activation of PKG and not PKA.
出处
《中国应用生理学杂志》
CAS
CSCD
2000年第1期33-36,共4页
Chinese Journal of Applied Physiology
关键词
多巴胺
血管平滑肌细胞
DA-1受体
钙激活钾通道
dopamine
vascular smooth muscle cell
calcium activated potassium channel
DA 1 receptor
