BKCa增龄变化及其与血压的相关性

CHANGES OF BKCa DURING AGING AND IT'S CORRELATION WITH BLOOD PRESSURE

目的:探讨大电导钙激活钾通道(BKCa,MaxiK)增龄变化及其与血压水平的关系。方法:选取雄性9、15、21、27、33周龄自发高血压大鼠(SHR)及对照组正常血压大鼠(WKY),每周龄两类大鼠各4只;测定各周龄SHR和WKY的腹主动脉血压;分离肠系膜小动脉及其血管平滑肌细胞;利用膜片钳全细胞模式记录肠系膜小动脉VSMCs钾电流、用四乙胺(TEA)阻断BKCa后的电流、膜电容,以计算BKCa电流值、BKCa电流密度;探讨BKCa电流密度增龄变化与血压的关系。结果:SHR肠系膜小动脉血管平滑肌细胞(VSMCs)BKCa电流密度随增龄降低,而WKY随增龄的变化无统计学意义(P>0.05);SHR肠系膜小动脉VSMCs BKCa电流密度与腹主动脉MABP高度相关(r=-0.7174),而WKY肠系膜小动脉VSMCs BKCa电流密度与腹主动脉MABP低度相关(r=-0.4832)。结论:BKCa电流和电流密度随增龄衰减,血压水平是衰减程度的重要反应;BKCa电流密度与血压水平高度相关。

Aim： To investigate the changes of large-conductance calcium-activated potassium channels（BKCa, MaxiK） during aging and relations between the changes and blood pressure. Methods： 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 mesenterie 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. Results： 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 signifi- cance（P 〉 0.05）. The BKCa current density was extremely correlative with MABP in SHR（the values of r were -0.7174）, in WKY, the BKCa current density was correlative with MABP（ r = -0.4832）. Conclusion： 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.