• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>American Journal of Physiology >KCa channel insensitivity to Ca2+ sparks underlies fractional uncoupling in newborn cerebral artery smooth muscle cells.
【24h】

KCa channel insensitivity to Ca2+ sparks underlies fractional uncoupling in newborn cerebral artery smooth muscle cells.

机译：KCa通道对Ca2 +火花的不敏感性是新生脑动脉平滑肌细胞中部分解偶联的基础。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In smooth muscle cells, localized intracellular Ca2+ transients, termed "Ca2+ sparks," activate several large-conductance Ca2+-activated K+ (KCa) channels, resulting in a transient KCa current. In some smooth muscle cell types, a significant proportion of Ca2+ sparks do not activate KCa channels. The goal of this study was to explore mechanisms that underlie fractional Ca2+ spark-KCa channel coupling. We investigated whether membrane depolarization or ryanodine-sensitive Ca2+ release (RyR) channel activation modulates coupling in newborn (1- to 3-day-old) porcine cerebral artery myocytes. At steady membrane potentials of -40, 0, and +40 mV, mean transient KCa current frequency was approximately 0.18, 0.43, and 0.26 Hz and KCa channel activity [number of KCa channels activated by Ca2+ sparksxopen probability of KCa channels at peak of Ca2+ sparks (NPo)] at the transient KCa current peak was approximately 4, 12, and 24, respectively. Depolarization between -40 and +40 mV increased KCa channel sensitivityto Ca2+ sparks and elevated the percentage of Ca2+ sparks that activated a transient KCa current from 59 to 86%. In a Ca2+-free bath solution or in diltiazem, a voltage-dependent Ca2+ channel blocker, steady membrane depolarization between -40 and +40 mV increased transient KCa current frequency up to approximately 1.6-fold. In contrast, caffeine (10 microM), an RyR channel activator, increased mean transient KCa current frequency but did not alter Ca2+ spark-KCa channel coupling. These data indicate that coupling is increased by mechanisms that elevate KCa channel sensitivity to Ca2+ sparks, but not by RyR channel activation. Overall, KCa channel insensitivity to Ca2+ sparks is a prominent factor underlying fractional Ca2+ spark uncoupling in newborn cerebral artery myocytes.
机译：在平滑肌细胞中，称为“ Ca2 +火花”的局部细胞内Ca2 +瞬变激活了几个大电导的Ca2 +激活的K +（KCa）通道，从而产生了瞬态KCa电流。在某些平滑肌细胞类型中，很大比例的Ca2 +火花不会激活KCa通道。这项研究的目的是探索部分Ca2 +火花-KCa通道耦合基础的机制。我们调查了膜去极化或ryanodine敏感的Ca 2+释放（RyR）通道激活是否调节新生（1-3天大）猪脑动脉心肌细胞的偶联。在-40、0和+40 mV的稳定膜电位下，平均瞬时KCa电流频率约为0.18、0.43和0.26 Hz，并且KCa通道活动性[Ca2 +激活的KCa通道数会激发出在Ca2 +峰值处KCa通道的开放概率瞬时KCa电流峰值处的电火花（NPo）分别约为4、12和24。 -40至+40 mV之间的去极化会增加KCa通道对Ca2 +火花的敏感性，并将激活瞬态KCa电流的Ca2 +火花百分比从59％提高到86％。在不含Ca2 +的浴液或地尔硫卓中，电压依赖性Ca2 +通道阻滞剂在-40至+40 mV之间稳定地进行膜去极化，可将瞬态KCa电流频率提高至大约1.6倍。相比之下，RyR通道激活剂咖啡因（10 microM）增加了平均瞬态KCa电流频率，但并未改变Ca2 + spark-KCa通道耦合。这些数据表明，通过提高KCa通道对Ca2 +火花的敏感性的机制可以增强耦合，但不能通过RyR通道激活来增强耦合。总体而言，KCa通道对Ca2 +火花的不敏感性是新生脑动脉肌细胞中部分Ca2 +火花解偶联的重要因素。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号