Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University/Key Laboratory of Environmental and Gene-Related Diseases (Xi'an Jiaotong University), Chinese Ministry of Education, No. 277 West Yanta Road, Xi'an, Shaanxi, 710061, China.
J Physiol Biochem. 2013 Dec;69(4):945-55. doi: 10.1007/s13105-013-0273-4. Epub 2013 Jul 20.
Abnormally functioning K(+) channels during aging might contribute to increased arterial tone of vascular smooth muscle cells. However, changes in large conductance calcium-activated potassium (BKca) channel current density and channel protein composition during aging are not fully understood and are currently investigated here. Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were grouped by age into very young (4-6 weeks), young (16-18 weeks), and adult (40-42 weeks) rats. BKca current was measured using a whole cell patch clamp in vascular smooth muscle cells from rat mesenteric arteries. BKca channel and subunits were measured using confocal imaging and real-time reverse transcriptase polymerase chain reaction techniques. Systolic and diastolic blood pressure increased significantly with age in both SHR and WKY rats. The expression of BKca α subunits increased in plasma membrane and cytoplasm in both SHR and WKY rats during aging, but had a larger increase in the cytoplasm in SHR than in WKY rats. BKca current density increased with aging in SHR but not in WKY rats. The relative abundance of BKca α and β1 mRNA transcripts changed minimally or not at all with aging in both SHR and WKY rats. In conclusion, plasma membrane BKca protein increased with aging in both SHR and WKY rats. Increases in cytoplasmic BKca protein and in BKca current were greater in SHR than WKY rats.
衰老过程中异常功能的 K(+) 通道可能导致血管平滑肌细胞的动脉张力增加。然而，目前还不完全了解衰老过程中大电导钙激活钾 (BKca) 通道电流密度和通道蛋白组成的变化，并正在对此进行研究。自发性高血压大鼠 (SHR) 和 Wistar-Kyoto (WKY) 大鼠按年龄分为非常年轻 (4-6 周)、年轻 (16-18 周) 和成年 (40-42 周) 大鼠。使用血管平滑肌细胞的全细胞膜片钳技术在大鼠肠系膜动脉中测量 BKca 电流。使用共聚焦成像和实时逆转录聚合酶链反应技术测量 BKca 通道和亚基。在 SHR 和 WKY 大鼠中，收缩压和舒张压随年龄增长显著增加。在 SHR 和 WKY 大鼠中，BKca α 亚基的表达在衰老过程中在质膜和细胞质中均增加，但在 SHR 中细胞质中的增加大于 WKY 大鼠。BKca 电流密度随 SHR 大鼠的衰老而增加，但在 WKY 大鼠中则没有。在 SHR 和 WKY 大鼠中，BKca α 和 β1 mRNA 转录本的相对丰度随年龄变化极小或没有变化。总之，在 SHR 和 WKY 大鼠中，质膜 BKca 蛋白随年龄增长而增加。在 SHR 大鼠中，细胞质 BKca 蛋白和 BKca 电流的增加大于 WKY 大鼠。
