茶氨酸提高运动能力的中枢机制

目的:建立大鼠一次性力竭游泳模型,研究茶氨酸对大鼠纹状体递质性氨基酸及谷氨酸受体蛋白含量与酪氨酸磷酸化水平的影响,从而探讨其对提高运动能力的中枢机制.方法:雄性SD大鼠随机分为正常对照组、茶氨酸高、中、低剂量(400,200,100 mg·kg-1)组,每组10只.各组大鼠适应性饲养1周后ig给药,正常对照组ig给予等体积生理盐水,共30 d.第31天,比较各组大鼠游泳至力竭时间;断头取纹状体,高效液相色谱测定纹状体匀浆中谷氨酸(glutamic acid,Glu)、甘氨酸(glycine,Gly)、γ-氨基丁酸(γ-aminobutyric acid,GABA)与天冬氨酸(aspartic acid,ASP)含量,通过免疫印迹法与免疫沉淀法测定N-甲基-D-天冬氨酸受体亚基(N-methyl-D-aspartate receptor subunits 2A,NR2A)蛋白含量与酪氨酸磷酸化水平.结果:茶氨酸有效延长大鼠游泳时间(149.4±4.0),(164.7 ±4.1)min,(P＜0.01),高剂量茶氨酸显著提高纹状体中Glu含量(10 063.2±359.5)μmol·L-1;与对照组比较,高剂量茶氨酸提高NR2A蛋白相对含量(134.1±3.6)与酪氨酸磷酸化水平(123.2±4.4,对照组为100,显著降低GABA含量(1 881.3±336.1)βmol·L-1,与正常对照组(2 237.1±198.4) μmol· L-1比较,P ＜0.05.结论:茶氨酸能缓解急性运动导致的中枢神经系统兴奋性抑制,从而提高运动能力,机制可能与其提高兴奋性神经递质含量降低抑制性神经递质含量及提高谷氨酸受体活性有关.

Effect and Mechanism of L-theanine on Improving Exercise Capacity in Rats

Objective:To investigate the influence of L-theanine on amino acids neurotransmitter and GluRs in rats by acute exhaustion swimming and mechanism of L-theanine improves exercise capacity.Method:SD male rats were randomly divided into high,middle and low dose(400,200,100 mg · kg-1,ig) groups and normal control group,ig,(n=10,in each group).After one week,each group was started to give L-theanine for 30 days.The normal control group was given normal saline.On the day 31,rat exhaustive swimming time was measured.Meanwhile,Glu,Gly,GABA and Asp of corpus striatum in rats were determined by HPLC.Immunoprecipitation and immunoblotting were applied to analyze the level of NR2A and tyrosine phosphorylation.Result:Compared with the normal control group,swimming time in high and middle dose groups increased significantly(149.4±4.0),(164.7±4.1)min,(P<0.01)].Level of Glu,NR2A,tyrosine phosphorylation showed obviously higher in high dose group than the normal control group (10 063.2±359.5)μmol · L-1,(134.1±3.6),(123.2±4.4),(P<0.05)].High dose group also showed lower GABA(1 881.3±336.1)μmol · L-1 level than normal control group(2 237.1±198.4) μmol·L-1(P<0.05).Conclusion:L-theanine has the effect of improving exercise capacity in rats possibly through enhancing Glu,NMDAR2A,tyrosine phosphorylation level and inhibiting the synthesis or secretion of GABA in brain.