摘要
目的探讨自发性高血压大鼠(SHR)大电导钙激活钾通道(BKCa,MaxiK)增龄的变化及其与血压水平的关系。方法选取雄性SHR及正常大鼠9、15、21、27、33周龄各6只。测定各周龄SHR和正常大鼠腹主动脉血压;利用膜片钳全细胞模式记录肾动脉血管平滑肌细胞(VSMCs)钾电流、用四乙胺(TEA)阻断BKCa后的电流、膜电容(Cm),计算BKCa电流值和BKCa电流密度。统计分析BKCa电流密度和其它各参数的增龄变化,及其和血压之间的相关性。结果不同周龄SHR腹主动脉平均动脉压(MABP)均明显升高,正常大鼠MABP始终正常;SHR和正常大鼠腹主动脉血压都有升高趋势,与同周龄正常大鼠相比,SHR腹主动脉血压升高更明显(P均<0.001)。SHR肾动脉VSMCs Cm随增龄增大,正常大鼠则无显著变化。SHR肾动脉VSMCs BKCa电流密度随增龄显著降低,电容逐渐增大,而正常大鼠随增龄的变化无统计学意义(P>0.05)。SHR肾动脉VSMCs BKCa电流密度、Cm与腹主动脉MABP高度负相关(r=-0.7962,r=-0.7361),正常大鼠肾动脉VSMCs BKCa电流密度与腹主动脉MABP低度相关(r=-0.4761)。结论SHR大鼠BKCa电流密度随增龄降低,电容随增龄增大,其过程复杂,并与血压水平有高度相关性。
Objective To observe the changes of large-conductance calcium-activated potassium channels（ BK- Ca,MaxiK） during aging and its relationship with blood pressure. Methods Thirty male spontaneously hyper-tensive rats（SHR） and normal rats aged 9, 15, 21, 27, 33 weeks were selected as SHR group and control group. Abdominal aortic blood pressure of rats in SHR and control groups were measured. The potassium current, the current of BKCa was blockaded by Tetraethylammonium（TEA） and the capacitance membrane（Cm） of the vascular smooth muscle cells（VSMCs） of renal artery were recorded using whole cell patch clamp, and the BKCa current, the potassium current and the BKCa current density were calculated. Results The mean abdominal aortic blood pressure（MABP） of SHR was obviously higher than normal（ P 〈 0. 001 ） , while MABP of the normal rats was still normal. The MABP of SHR and normal rats all had tended to heighten with aging. The Cm of SHR group increased during aging, but normal group did not. The BKCa current density of SHR group decreased during aging, but the changes of normal group were not significant （P 〉 O. 05 ）. The BKCa current density and Cm were negatively related with MABP in SHR group（r = -0. 7962, r = -0. 7361 ）, and BKCa current density was poorly related with MABP in normal group（ r = -O. 4761 ）. Conclusions BKCa current density of SHR attenuated with aging. The process of attenuation is complex and have high correlation with blood pressure during aging.
出处
《国际内科学杂志》
CAS
2008年第11期625-628,636,共5页
International Journal of Internal Medicine
基金
安徽省教育厅课题(2006KJ354B)
关键词
肾动脉
膜片钳技术
大电导钙激活钾通道
高血压
Renal artery
Patch clamp technique
Large-conductance calcium-activated potassium channel
Hypertension
