高强度间歇训练对SD大鼠骨骼肌交感缩血管反应和功能性抗交感的影响:NO和α_1-AR的作用

Effects of High-intensity Interval Training on Sympathetic Vasoconstriction in Skeletal Muscle of SD Rats: Role of NO and α_1-AR

观察8周高强度间歇训练(HIIT)对骨骼肌交感缩血管反应和功能性抗交感的影响并探讨一氧化氮(NO)和α_1-肾上腺素能受体(α_1-AR)在其中的作用机制。方法:30只健康雄性SD大鼠随机分为安静对照组(S,n=15)和运动组(E,n=15),S组保持安静状态,E组进行8周HIIT。实验后麻醉动物,电刺激腰部交感神经干诱导缩血管反应,电刺激胫神经诱发小腿三头肌收缩。分别于未灌注药物、灌注α_1-AR阻断剂(哌唑嗪)、灌注哌唑嗪联合一氧化氮合酶(NOS)抑制剂(NG-硝基-L-精氨酸甲酯,LNAME)时记录骨骼肌安静时及收缩时的股血管电导(FVC)的变化。交感缩血管反应用FVC对交感电刺激的变化率(%FVC)表示,功能性抗交感用安静时FVC对交感电刺激的变化率与肌肉收缩时的差值表示(△%FVC=%FVC安静-%FVC肌肉收缩)。结果:1)未灌注药物时,安静状态下,E组低频(2 Hz)交感刺激诱导的%FVC高于S组(P<0.05),而高频(5 Hz)刺激时组间无显著性差异(P>0.05);肌肉收缩状态下E组和S组间%FVC无显著性差异(P>0.05)。灌注哌唑嗪时,安静及肌肉收缩状态下,S组和E组%FVC均显著性下降(P<0.05),组间比较则无显著性差异(P>0.05)。灌注哌唑嗪联合L-NAME时,S组安静及肌肉收缩时%FVC显著性升高(P<0.05);E组安静状态下2 Hz交感刺激时的%FVC增加(P<0.05),肌肉收缩时无显著性变化(P>0.05)。2)未灌注药物时,E组△%FVC高于S组(P<0.05)。灌注哌唑嗪时,E组2 Hz交感刺激时的△%FVC下降(P<0.05),组间比较无显著性差异(P>0.05)。灌注哌唑嗪+L-NAME时,S组和E组△%FVC均无显著性变化(P>0.05)。结论:HIIT通过增强骨骼肌收缩时NO对α_1-AR依赖性交感缩血管反应的抑制作用而改善功能性抗交感。

Objective:The purpose of this study is to observe the effect of high-intensity interval training(HIIT)of 8 weeks on sympathetic vasoconstriction and functional sympatholysis in skeletal muscle and investigate the mechanism of nitric oxide(NO)andα1-adrenoreceptor(α1-AR).Methods:Thirty healthy SD rats randomized to sedentary(S,n=15)and exercise(E,n=15)groups.Animal in S group maintained resting state while those in E group performed HIIT lasting for 8 weeks.After experiment,rats were anesthetized,sympathetic vasoconstriction responsiveness was induced by electrostimulation of the lumbar sympathetic chain and the triceps surae muscle group contracted by electrostimulation of tibial nerve.Femoral vascular conductance(FVC)was recorded at rest and during contraction of skeletal muscle in non-administration of drug,administration ofα1-AR blockade(Prazosin)and Prazosin combined with nitric oxide synthase(NOS)inhibitor(NG-nitro-L-arginine methyl ester,L-NAME).Sympathetic vasoconstrictor responsiveness was expressed by percentage change in FVC(%FVC)in response to sympathetic electrostimulation and functional sympatholysis was calculated as the difference between the percentage change in FVC in response to sympathetic electrostimulation at rest and during muscular contraction(?驻%FVC=%FAVCrest-%FAVCcontraction).Results:1)Sympathetic vasoconstrictor responsiveness(%FVC):During non-administration of drug,%FVC was increased(P<0.05)in E compared to S group at low,but not high(P>0.05)electrostimulation frequencies at rest,whereas%FVC was not different(P>0.05)between groups during contraction.Administration of Prazosin reduced(P<0.05)%FVC in S and E groups at rest and during contraction,and abolished group differences in%FVC.Administration of Prazosin and L-NAME increased%FVC(P<0.05)in S at rest and during contraction,whereas in E group%FVC was increased(P<0.05)in response to sympathetic stimulation at 2 Hz at rest and unchanged(P>0.05)during contraction.2)Functional sympatholysis(?驻%FVC):During non-administration of drug,?驻%FVC of E group enhanced(P<0.05),however the above effect were abolished by Prazosin.Subsequent NOS inhibition did not alter(P>0.05)?驻%FVC in S or ET groups.Conclusion:HIIT enhanced NO mediatedα1-AR dependent sympathetic vasoconstriction during skeletal muscle contraction and improved functional sympatholysis.