Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya, 3, 142290, Russia.
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya, 3, 142290, Russia; Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Butlerova 5А, 117485, Russia.
Arch Biochem Biophys. 2019 Oct 15;674:108109. doi: 10.1016/j.abb.2019.108109. Epub 2019 Sep 18.
to investigate α2-AR subtype distribution and the relationship between receptor amounts and their functionality in normotensive and spontaneously hypertensive rats.
experiments were performed on left ventricular cardiomyocytes isolated from Wistar rats and SHR (2-2.5 months). Molecular routine tools (RT-PCR, Western blotting, immunocytochemistry) were used for semi-quantitative estimation of α2-AR subtypes. Fluorescence of both the Ca-dependent and NO-sensitive probes were used to define functionality of α2-AR, evaluated by changes in the dynamics of spontaneous Ca-transients and NO production in cardiomyocytes in response to the α2-AR agonist application.
percentage of the three known α2-AR subtypes in Wistar and SHR cardiomyocytes is not principally different. Total amounts of α2A-AR subtype in SHR increases, for both the sarcolemmal and intracellular receptor pools. Total number of α2B-AR is also significantly higher in hypertensive rats with an increase in the sarcolemmal, but not the intracellular immunoreactivity. For α2C-AR subtype, no significant differences between Wistar and SHR were identified, despite the fact that its amounts in cardiomyocytes are somewhat higher than the other two subtypes. Notwithstanding the increased expression of α2-AR subtypes in SHR, α2-AR-agonist guanabenz was ineffective in suppression of spontaneous Ca-transients, as well as the lowering of free calcium levels in the cytosol. Guanabenz-induced NO synthesis is well correlated with the Ca-loading into sarcoplasmic reticulum and actually decreased in SHR cardiomyocytes.
data indicate α2-AR dysfunction and ineffectiveness of α2-AR-mediated signaling pathways in this model of cardiovascular pathologies. Results can be used for clinical practice for more effective control of cardiovascular functions in various disease states.
研究α2-AR 亚型分布以及受体数量与其在正常血压和自发性高血压大鼠中的功能之间的关系。
在 Wistar 大鼠和 SHR（2-2.5 个月）的左心室心肌细胞中进行实验。使用分子常规工具（RT-PCR、Western 印迹、免疫细胞化学）对半定量估计 α2-AR 亚型。使用 Ca 依赖性和 NO 敏感探针的荧光来定义 α2-AR 的功能，通过应用 α2-AR 激动剂后心肌细胞中自发 Ca 瞬变和 NO 产生的动力学变化来评估。
Wistar 和 SHR 心肌细胞中三种已知的 α2-AR 亚型的比例没有根本不同。在 SHR 中，α2A-AR 亚型的总数量增加，无论是在质膜还是细胞内受体池中。高血压大鼠的 α2B-AR 总数也显著增加，质膜中的增加，但细胞内免疫反应性没有增加。对于 α2C-AR 亚型，在 Wistar 和 SHR 之间没有发现显著差异，尽管其在心肌细胞中的数量略高于其他两种亚型。尽管 SHR 中 α2-AR 亚型的表达增加，但 α2-AR 激动剂胍那苄在抑制自发 Ca 瞬变以及降低细胞质中游离钙水平方面无效。胍那苄诱导的 NO 合成与肌浆网中的 Ca 加载密切相关，实际上在 SHR 心肌细胞中降低。
数据表明，在这种心血管病理模型中，α2-AR 功能障碍和 α2-AR 介导的信号通路无效。结果可用于临床实践，以在各种疾病状态下更有效地控制心血管功能。
