Impact of α1-adrenoceptor expression on contractile properties of vascular smooth muscle cells
Impact of α1-adrenoceptor expression on contractile properties of vascular smooth muscle cells
复制标题
DOI：
10.1152/ajpregu.00076.2007
复制
发表时间：
2007-09-01
影响因子：
2.8
通讯作者：
Patzak, Andreas
中科院分区：
文献类型：
--
作者：
Gericke, Adrian;Martinka, Peter;Patzak, Andreas
低频血压振荡（迈耶波）被讨论为血管张力交感调节的标志。然而，决定脉管系统对交感神经刺激的频率响应的因素尚未完全了解。可能的机制包括与α1-肾上腺素能受体（α1-AR）相关的功能和参与血管收缩反应的受体后过程。本研究的目的是检验以下假设：α1-AR 的表达水平及其亚型分布决定 α1-AR 介导的血管平滑肌细胞 (VSMC) 收缩的速度和幅度。将α1A-、α1B-和α1D-AR亚型转染至大鼠主动脉的VSMC中，并通过共聚焦显微镜进行免疫细胞化学表征。使用视频显微镜对分离的细胞进行功能研究。 α1-AR激动剂去氧肾上腺素产生剂量依赖性的VSMC收缩。与对照组相比，所有转染组对去氧肾上腺素更敏感。转染细胞的最大收缩速度几乎加倍。然而，三个转染组之间观察到的参数没有差异。所有组中对 KCl 膜去极化反应的收缩特性相似。总之，α1-AR密度决定了VSMC中α1-AR介导的收缩的速度和敏感性。 α1-AR亚型分布似乎不影响交感神经刺激的血管收缩。
Low- frequency blood pressure oscillations ( Mayer waves) are discussed as a marker for sympathetic modulation of vascular tone. However, the factors that determine the frequency response of the vasculature to sympathetic stimuli are not fully understood. Possible mechanisms include functions related to alpha 1- adrenergic receptors ( alpha 1- AR) and postreceptor processes involved in the vascular contractile response. The purpose of the present study was to examine the hypothesis that expression levels of alpha 1- AR and their subtype distribution determine velocity and magnitude of alpha 1- AR- mediated vascular smooth muscle cell ( VSMC) contraction. alpha 1A-, alpha 1B-, and alpha 1D- AR subtypes were transfected into VSMCs from rat aorta and characterized immunocytochemically via confocal microscopy. Functional studies in isolated cells were performed using video microscopy. The alpha 1- AR agonist phenylephrine produced dose- dependent contractions of VSMCs. All transfected groups were more sensitive to phenylephrine compared with controls. Maximal contraction velocity almost doubled in transfected cells. However, no differences in observed parameters were found between the three transfected groups. Contractile properties in response to membrane depolarization with KCl were similar in all groups. In conclusion, alpha 1- AR density determines velocity and sensitivity of alpha 1- AR- mediated contraction in VSMCs. alpha 1- AR subtype distribution does not appear to influence vasoconstriction to sympathetic stimuli.