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目的:观测研究下坡(离心)运动对大鼠骨骼肌肌浆网Ca2+-ATP酶活性,Ca2+摄取与释放在量与时程上的影响。此外,测定离子载体的刺激作用,即测定在含与不含(Ca2+离子载体)A23187时Ca2+-ATP酶活性的比值,用以评定囊泡的完整性。方法:成年雄性SD大鼠随机分为对照与离心运动组,离心运动的大鼠分别于运动后即刻,4,24,48,72和144h后取样(n=7).离心运动方式采用90min持续跑台下坡运动(-16°;15m/min)。取大鼠红股肌制备组织匀浆,测定肌浆网Ca2+-ATP酶活性,Ca2+摄取与释放。结果:与对照组[19.25±1.38nmol·min-1·(mg protein)-1]相比,肌浆网Ca2+摄取分别于运动后即刻和4h下降了29% and 36%(P<0.05),24h依然降低(P<0.05).肌浆网Ca2+释放与对照组[31.06±2.36nmol·min-1·(mg protein)-1]相比,也分别于运动后即刻和4h下降了37% and 39%(P<0.05),24h持续降低(P<0.05).用含离子载体测定的肌浆网Ca2+-ATP酶活性运动后4h降低了31%(P<0.05),并于运动后24h仍然降低(P<0.05)。运动后,含与不含A23187时测定的Ca2+-ATP酶活性的比值未见显著性改变,表明该运动没有明显改变肌浆网膜的完整性。结论:一次性低强度,长时间下坡运动导致肌浆网功能长时间降低,运动后恢复期两天尚未完全恢复,亦可构成离心运动诱导的骨骼肌某些功能降低的基础。提示这些变化可能产生于离心收缩时肌节长度不匀一性所造成的张力应激。
Objective: To observe the effects of downhill (eccentric) exercise on the sarcoplasmic reticulum Ca2 + -ATPase activity and Ca2 + uptake and release in skeletal muscle of rats. In addition, the effect of ionophore stimulation was determined by measuring the ratio of Ca2 + -ATPase activity in the presence and absence of (Ca2 + ionophore) A23187 to assess vesicle integrity. Methods: Adult male Sprague-Dawley rats were randomly divided into control group and eccentric exercise group. Centrifugal rats were sampled immediately after exercise, and were sampled after 4, 24, 48, 72 and 144 hours (n = 7) Downhill running treadmill (-16 °; 15m / min). Tissue homogenate was prepared from the red muscle of rat and the Ca2 + -ATPase activity and Ca2 + uptake and release were analyzed. Results: Compared with the control group [19.25 ± 1.38nmol · min-1 · mg-1], Ca2 + uptake in sarcoplasmic reticulum decreased by 29% and 36% (P <0.05) (P <0.05). Compared with the control group [31.06 ± 2.36nmol · min-1 · mg protein -1], Ca2 + release in sarcoplasmic reticulum decreased by 37% at 4h (P <0.05), and the activity of Ca2 + -ATPase in sarcoplasmic reticulum decreased 31% (P <0.05) 4 h after exercise, Decreased (P <0.05). There was no significant change in the ratio of Ca2 + -ATPase activity measured with and without A23187 after exercise, indicating that the exercise did not significantly alter sarcoplasmic reticulum integrity. CONCLUSION: One-off low-intensity exercise and long-time downhill exercise lead to a long-term reduction of sarcoplasmic reticulum function, which has not yet recovered completely within two days after exercise. It may also form the basis of eccentric exercise-induced decrease of some functions of skeletal muscle. Suggesting that these changes may be caused by eccentric contraction of suture length irregularity caused by tension stress.