Yang Yu-Wen, Kan Jing-Bao, Kong Xiang-Quan
Department of Cardiology of Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2009 Nov;25(4):511-5.
To investigate the changes of large-conductance calcium-activated potassium channels (BKCa, MaxiK) during aging and relations between the changes and blood pressure.
Male spontaneously hypertensive rats (SHR) aged 9, 15, 21, 27, 33 weeks (the number of each weeks SHR was 4) were selected as hypertension group rats, corresponding gender, weeks and number Wistar-Kyoto rats (WKY) as control group rats. Blood pressure of abdominalis aorta of each weeks SHR and WKY were measured by BL-420F experimental system of biological function. The arteria mesenteric minor (AMM) were isolated in blunt dissection method. The vascular smooth muscle cells (VSMCs) of AMM were isolated with prolease. The potassium current, the current after BKCa were blockaded by Tetraethylammonium (TEA) and the capacitance of membrane (Cm) of VSMCs of AMM were recorded with using whole cell patch clamp, and calculated the BKCa current and the BKCa current density. Probe the correlation of the changes of BKCa current density with MABP during aging.
The potassium current density and BKCa current density of VSMCs of AMM of SHR were decreasing during aging, however, the changes of WKY had no statistically significance (P > 0.05). The BKCa current density was extremely correlative with MABP in SH R (the values of r were -0.7174), in WKY, the BKCa current density was correlative with MAB P r = -0.4832.
BKCa current and current density attenuate with aging, the level of blood pressure is response of the attenuated degree. The BKCa current density is extremely correlative with the blood pressure.
研究大电导钙激活钾通道（BKCa，MaxiK）在衰老过程中的变化及其与血压的关系。
选取9、15、21、27、33周龄龄雄性的雄性自发性高血压大鼠（SHR）（各周龄SHR数量均为4只）作为高血压组大鼠，选取相应性别、周龄及数量的Wistar-Kyoto大鼠（WKY）作为对照组大鼠。采用BL-420F生物机能实验系统测量各周龄SHR和WKY腹主动脉血压。用钝性分离法分离肠系膜小动脉（AMM）。用胰蛋白酶分离AMM的血管平滑肌细胞（VSMC）。采用全细胞膜片钳记录AMM的VSMC的钾电流、用四乙铵（TEA）阻断BKCa后的电流以及细胞膜电容（Cm），并计算BKCa电流和BKCa电流密度。探讨衰老过程中BKCa电流密度变化与平均动脉血压（MABP）的相关性。
衰老过程中SHR的AMM的VSMC的钾电流密度和BKCa电流密度降低，而WKY的变化无统计学意义（P>0.05）。SHR中BKCa电流密度与MABP呈高度相关（r值为-0.7174），WKY中BKCa电流密度与MABP相关（r=-0.4832）。
BKCa电流和电流密度随衰老而衰减，血压水平是衰减程度的反映。BKCa电流密度与血压高度相关。
