运动缓解老年高血压大鼠脑动脉Ca_L通道的功能重构

Exercise training attenuates remodeling of Ca_L channel in cerebral artery of aging hypertensive rats

目的探讨运动对衰老高血压大鼠脑动脉平滑肌Ca_L通道功能的影响。方法雄性3月龄正常血压（WKY）大鼠、自发性高血压大鼠（SHR）各18只;16月龄WKY大鼠和SHR各36只,再随机分成安静组和运动组,各18只。运动组以16~18 m/min进行8周跑台运动（每天60 min,每周5天）。8周后,测定各组大鼠体重、心脏重量,采用全细胞膜片钳技术和Western blot测定大鼠脑动脉Ca_L通道功能和Ca_L通道α1C亚基蛋白的表达。结果（1）SHR心率和收缩压均显著高于同龄WKY大鼠,老年大鼠收缩压较同类别青年组均显著增高;青年组SHR脑动脉Ca_L通道电流密度及其α1C亚基蛋白表达均显著高于WKY大鼠,在老年组差异无显著性,且均低于同类别青年组。（2）运动后衰老大鼠心重指数（心脏重量/体重）较同类别安静组均显著增加;运动显著降低衰老SHR收缩压,增加衰老SHR脑动脉Ca_L通道电流密度及其α1C亚基蛋白表达。结论衰老SHR脑动脉Ca_L通道功能下调,运动缓解衰老引起的Ca_L通道功能重构。

Aim To investigate the effects of exercise training on the function of the Ca_L channels in cerebral arterial smooth muscle cells of aging spontaneously hypertensive rats. Methods 18 3-month-old male Wistar-Kyoto（ WKY） rats and 18 spontaneously hypertensive rats（ SHR） were used,besides,16-month-old male WKY and SHR were randomly assigned into either a sedentary group or an exercise-trained group,each group contained 18 rats. The rats in exercise-trained groups ran on a motor treadmill（ 60 min/d,5 d/w） at 16 ~ 18 m/min for 8 weeks. After 8 weeks training,body weight and heart weight among these groups were measured. The Ca_L channel function and the expression of Ca_L channel α1 C protein in cerebral artery were measured by whole-cell patch-clamp technique and Western blot. Results（ 1） Aging effects： Both heart rate and systolic blood pressure in SHR were much higher than those of the same age WKY rats,the systolic blood pressure in 16-month-old rats were significantly higher than the same strain in 3-month-old rats; The Ca_L channel current density and Ca_L channel α1 C protein expression in young SHR were extremely increased compared with WKY,whereas aging markedly decreased Ca_L channel current density and Ca_L channel α1 C protein expression in both hypertensive and normotensive rats with no significant differences between them.（ 2） Exercise effects： The heart weight index（ heart weight/body weight） in aging exercise-trained groups were markedly higher than those in sedentary strains; Exercise training greatly lowered the systolic blood pressure,and increased Ca_L channel current density and Ca_L channel α1 C protein expression in SHR. Conclusion Aging reduced Ca_L channel function of cerebral artery from SHR,while exercise training attenuated remodeling of Ca_L channel.