老年大鼠心肌肌浆网功能的改变  

Alterations in calcium transport of myocardial sarcoplasmic reticulum in aged rats

作　　者：齐永芬[1] 刘秀华[2] 王士雯[2] 杨军[1] 祁芸芸[1] 庞永正[1] 唐朝枢[1] 

机构地区：[1]北京大学第一医院心血管病研究所,100034 [2]解放军总医院老年心血管病研究所

出　　处：《中华老年医学杂志》2000年第5期354-357,共4页Chinese Journal of Geriatrics

摘　　要：目的　探讨老年大鼠心肌肌浆网 (SR)钙转运的改变及其在心脏收缩功能障碍中的作用。　方法　测定老年和成年Wistar大鼠心功能 ,取左心室肌组织制备肌浆网膜 ,采用Millipore滤过法测定心肌SRCa2 + 摄取、Ca2 + 释放和 3 H Ryanodine受体结合 ,并测定心肌SRCa2 + ATP酶活性。　结果　与成年组比较 ,老年组大鼠左室舒张末压 (LVEDP)升高 82 % (P <0 0 5 ) ,左室内压变化速率(±dp/dt)分别下降 8%和 2 4% (P <0 0 5 ) ;心肌SRCa2 + ATP酶活性〔(6 2 6± 1 2 2 )与 (12 34± 1 46 )μmolPi·mg-1protein·h-1,P <0 0 5〕与Ca2 + 摄取量〔(35 40± 3 5 7)与 (72 6 2± 8 10 )nmolCa2 + ·mg-1protein·min-1,P <0 0 5〕明显下降 ;老年心肌SR3 H Ryanodine受体结合最大值降低 37% (P <0 0 5 ) ,解离常数 (Kd)值无明显变化 ,且心肌SRCa2 + 释放速率明显降低〔(12 5 0± 2 2 9)与 (17 6 5± 1 93)nmolCa2 + ·mg 1protein·15s-1,P <0 0 5〕。　结论　老年大鼠心脏收缩功能下降 ,其机制涉及心肌SRCa2 + ATP酶活性降低所致的Ca2 + 摄取下降 ,及SR3 H Ryanodine受体结合量下降所致的Ca2 + 释放功能障碍。Objective To examine the status of sarcoplasmic reticulum (SR) with respect to Ca 2+ transport and its role in myocardial contractile decline in aged rats. Methods The cardiac function was monitored in aged and adult rats, respectively. Vesicles of sarcoplasmic reticulum (SR) was prepared from left ventricle. Myocardial SR calcium release, calcium uptake, and 3 H Ryanodine receptor binding were determined using Millipore filtration technique. The activity of SR Ca 2+ ATPase was also determined. Results Compared with the adult rats, left ventricular end diastolic pressure (LVEDP) increased (P<0 05) and the change rate of left ventricular endopressure (±dp/dt) decreased (P<0 05) in aged rats. The activities of SR Ca 2+ ATPase 〔(6 26±1 22) vs (12 34±1 46)μmol Pi·mg 1 protein·h 1 in adult rats, P<0 05〕 and the calcium uptake 〔(35 40±3 57) vs. (72 62±8 10) nmol Ca 2+ ·mg -1 protein·min 1 in adult rats, P<0 05〕 in the myocardium of the aged rats were reduced significantly. The Bmax of SR 3?H Ryanodine in the myocardium of the aged rats decreased to 37% (P<0 05) ,but there was no significant changes in Kd values between aged and adult groups. Calcium release was also decreased 〔(12 50±2 29) vs (17 65±1 93) nmol Ca 2+ ·mg -1 protein· 15 s -1 , P<0 05〕in aged myocardium. Conclusions The reduced cardiac contractile in aged rats might be associate with the decrease of calcium uptake resulted from the reduction of SR Ca 2+ ATPase activity, and also with the dysfunction of calcium release induced by the decrease of SR 3 H Ryanodine binding.

关 键 词：心肌肌浆网 功能 钙转运 ATP酶 钙通道 

分 类 号：R339.38[医药卫生—人体生理学]