衰老诱导大鼠肠系膜动脉平滑肌细胞BK_(Ca)通道β1亚基功能下调  

Aging induces functional downregulaiton of β1-subunit of BKCa channels in mesenteric arterial smooth muscle cells

作　　者：石丽君[1] 刘佰林[1] 刘雨佳[1] 陈渝[1] 

机构地区：[1]北京体育大学运动生理教研室,北京100084

出　　处：《中国老年学杂志》2014年第22期6385-6388,共4页Chinese Journal of Gerontology

基　　金：国家自然科学基金(31371201;31071033);北京市自然科学基金(5132017);新世纪优秀人才支持计划(NCET-11-0850)

摘　　要：目的：探讨衰老对大鼠肠系膜动脉平滑肌细胞大电导钙激活钾通道（BKCa）生物物理特性的影响。方法选用老年组（22～24月龄）和青年组（4～5月龄）雄性Wistar大鼠，采用膜片钳内面向外模式进行肠系膜动脉平滑肌细胞BKCa单通道记录。结果衰老组 BKCa通道平均开放概率（Po）和平均开放时间显著低于青年组；电压依赖性和钙敏感性亦显著下降；Tamoxifen （1μmol／L）可诱导两组 Po增加，但青年组增加百分比显著高于老年组。结论衰老诱导大鼠肠系膜动脉平滑肌细胞BKCa通道功能下调，以β1亚基功能下调更为显著。Objective To investigate the effects of aging on the biophysical properties of large-conductance Ca ^2＋-activated K＋（ BK-Ca） channel in rat mesenteric arterial smooth muscle cells .Methods Young （5 months） and Old （22～24 months） male Wistar rats were used.The single channel recording was performed by inside-out patch clamp configuration .Results Electrophysiological recording revealed that aging induced a decrease of the open probability and the mean open time ,but an increase of the mean closed time of BKCa channel .The Ca2＋/voltage sensitivity of BKCa channel was also decreased .Application of tamoxifen （1μmol/L） evoked nearly a 5-fold increase in the Po of BKCa channels in Young patches ,while only 1.6-fold increase in Old patches .Conclusions The aging induces functional downregulation of MaxiK channel in MA myocytes ,in which the suppression of β1-subunit function is more pronounced than α-subunit.

关 键 词：衰老 BK_Ca通道 肠系膜动脉 平滑肌细胞 生物物理特性 

分 类 号：R339.38[医药卫生—人体生理学]