We found that sinus bradycardia in members of a large family was associated with a mutation in the gene coding for the pacemaker HCN4 ion channel. Pacemaker channels of the sinoatrial node generate spontaneous activit...We found that sinus bradycardia in members of a large family was associated with a mutation in the gene coding for the pacemaker HCN4 ion channel. Pacemaker channels of the sinoatrial node generate spontaneous activity and mediate cyclic AMP(cAMP)-dependent autonomic modulation of the heart rate. The mutation associated with bradycardia is located near the cAMP-binding site; functional analysis found that mutant channels respond normally to cAMP but are activated at more negative voltages than are wild-type channels. These changes, which mimic those of mild vagal stimulation, slow the heart rate by decreasing the inward diastolic current. Thus, diminished function of pacemaker channels is linked to familial bradycardia.展开更多
目的从组织功能及细胞分子水平研究电压门控型钾通道(Kv通道)亚型在15-羟化二十碳四烯酸(15-HETE)致大鼠肺动脉收缩过程中的作用。方法采用组织浴槽血管环法,使用Kv通道阻断剂,确定受15-HETE调控大鼠肺动脉平滑肌细胞(PASMCs)膜上Kv亚型...目的从组织功能及细胞分子水平研究电压门控型钾通道(Kv通道)亚型在15-羟化二十碳四烯酸(15-HETE)致大鼠肺动脉收缩过程中的作用。方法采用组织浴槽血管环法,使用Kv通道阻断剂,确定受15-HETE调控大鼠肺动脉平滑肌细胞(PASMCs)膜上Kv亚型;使用RT-PCR和W estern b lotting技术观察受15-HETE调控PASMCs膜上Kv亚型。结果阻断Kv1.1,Kv1.2,Kv1.3和Kv1.6通道并不影响15-HETE诱导肺动脉血管收缩;15-HETE不影响PASMCs膜上Kv1.1和Kv1.2通道蛋白质表达;15-HETE下调PASMCs膜上Kv1.5和Kv2.1通道mRNA和蛋白质表达。结论缺氧可能是通过15-HETE这一介导因子抑制Kv1.5和Kv2.1通道,减少PASMCs膜上功能性Kv1.5和Kv2.1通道数量,导致PASMCs收缩。展开更多
目的通过风湿性心脏病(简称风心病)心房颤动(简称房颤)患者右心耳组织超极化激活环核苷酸门控阳离子通道-2(HCN2)基因mRNA表达检测,探讨其与房颤的可能关系。方法 28例风心病患者根据是否存在房颤,分为房颤组和窦性心律(简称窦律)组,术...目的通过风湿性心脏病(简称风心病)心房颤动(简称房颤)患者右心耳组织超极化激活环核苷酸门控阳离子通道-2(HCN2)基因mRNA表达检测,探讨其与房颤的可能关系。方法 28例风心病患者根据是否存在房颤,分为房颤组和窦性心律(简称窦律)组,术前均行心脏彩色多普勒超声检测,术中取右心耳组织,应用半定量聚合酶链式反应技术检测HCN2mRNA表达。结果房颤组右房径大于窦律组((59.2±10.9 mm vs 41.7±15.5mm,P<0.05);HCN2mRNA表达水平高于窦律组(0.911 9±0.7052 vs 0.4735±0.3909,P<0.05)。结论HCN2mRNA表达异常增高,可能与风心病房颤的发生相关。展开更多
文摘We found that sinus bradycardia in members of a large family was associated with a mutation in the gene coding for the pacemaker HCN4 ion channel. Pacemaker channels of the sinoatrial node generate spontaneous activity and mediate cyclic AMP(cAMP)-dependent autonomic modulation of the heart rate. The mutation associated with bradycardia is located near the cAMP-binding site; functional analysis found that mutant channels respond normally to cAMP but are activated at more negative voltages than are wild-type channels. These changes, which mimic those of mild vagal stimulation, slow the heart rate by decreasing the inward diastolic current. Thus, diminished function of pacemaker channels is linked to familial bradycardia.
文摘目的从组织功能及细胞分子水平研究电压门控型钾通道(Kv通道)亚型在15-羟化二十碳四烯酸(15-HETE)致大鼠肺动脉收缩过程中的作用。方法采用组织浴槽血管环法,使用Kv通道阻断剂,确定受15-HETE调控大鼠肺动脉平滑肌细胞(PASMCs)膜上Kv亚型;使用RT-PCR和W estern b lotting技术观察受15-HETE调控PASMCs膜上Kv亚型。结果阻断Kv1.1,Kv1.2,Kv1.3和Kv1.6通道并不影响15-HETE诱导肺动脉血管收缩;15-HETE不影响PASMCs膜上Kv1.1和Kv1.2通道蛋白质表达;15-HETE下调PASMCs膜上Kv1.5和Kv2.1通道mRNA和蛋白质表达。结论缺氧可能是通过15-HETE这一介导因子抑制Kv1.5和Kv2.1通道,减少PASMCs膜上功能性Kv1.5和Kv2.1通道数量,导致PASMCs收缩。
文摘目的通过风湿性心脏病(简称风心病)心房颤动(简称房颤)患者右心耳组织超极化激活环核苷酸门控阳离子通道-2(HCN2)基因mRNA表达检测,探讨其与房颤的可能关系。方法 28例风心病患者根据是否存在房颤,分为房颤组和窦性心律(简称窦律)组,术前均行心脏彩色多普勒超声检测,术中取右心耳组织,应用半定量聚合酶链式反应技术检测HCN2mRNA表达。结果房颤组右房径大于窦律组((59.2±10.9 mm vs 41.7±15.5mm,P<0.05);HCN2mRNA表达水平高于窦律组(0.911 9±0.7052 vs 0.4735±0.3909,P<0.05)。结论HCN2mRNA表达异常增高,可能与风心病房颤的发生相关。