力竭运动后大鼠脑皮质运动区谷氨酸受体NR2A蛋白含量及酪氨酸磷酸化水平的变化

目的:观察力竭运动前后大鼠脑皮质运动区NR2A蛋白含量及其自身酪氨酸磷酸化水平变化,分析二者之间的相关关系,为探讨中枢兴奋信号在运动中的传递机理以及运动性疲劳的中枢机制提供实验依据。方法:SD大鼠进行一次性力竭跑台运动。采用抗NR2A抗体和抗磷酸酪氨酸单抗以免疫沉淀法和免疫印迹法检测皮质运动区NR2A蛋白含量及酪氨酸磷酸化水平。结果:力竭运动后即刻,大鼠脑皮质运动区NR2A蛋白含量与安静组相比无显著性变化,运动后1小时与安静组和运动后即刻比较显著升高(P<0.05,P<0.01),运动后3小时NR2A蛋白含量下降,运动后恢复24小时大鼠脑皮质中NR2A蛋白含量显著低于安静组和运动后即刻组(P<0.01,P<0.05)。NR2A酪氨酸磷酸化水平力竭运动后与对照组相比呈升高趋势但无显著性差异,NR2A酪氨酸磷酸化水平与NR2A蛋白含量变化无显著相关。结论:(1)大鼠在力竭运动后即刻及恢复期过程中,大脑皮质运动区NR2A蛋白含量变化表现为下降,上升,再下降,表明运动过程中NR2A蛋白含量变化具有较敏感的可调控性,力竭运动后即刻NR2A蛋白含量的下降可能是导致中枢抑制的一个因素。(2)NR2A酪氨酸磷酸化水平在力竭运动后呈升高趋势,可能有利于维持中枢的兴奋性,提示运动过程中NR蛋白含量的变化可能是多方面原因造成的,受体蛋白含量与受体活性之间可能存在较为复杂的关系。     

长期中等强度运动对大鼠心肌组织金属硫蛋白的影响

目的:观察长期中等强度运动后大鼠心肌金属硫蛋白(MT)含量的变化,探讨金属硫蛋白对心肌的保护作用。方法:选用健康雄性SD大鼠40只,体重220～250g,随机分为安静对照组(A组);运动训练安静组(B组);中等强度运动训练(90分钟)+力竭组(C组);一次性力竭运动组(D组),每组10只。B、C组大鼠进行为期8周的中等强度运动。实验8周后,力竭组大鼠进行一次力竭运动。测定大鼠心肌组织中的MT含量、MDA含量和-SH含量。结果:(1)运动训练安静组和中等强度运动训练+力竭组大鼠心肌组织中MDA含量显著低于安静对照组(P<0.05),一次力竭运动组大鼠MDA显著高于安静对照组及运动训练安静组(P<0.05);(2)中等强度运动训练+力竭组大鼠-SH含量显著高于安静对照组和运动训练安静组(P<0.05),一次力竭运动组大鼠-SH含量显著低于安静对照组和运动训练安静组(P<0.05);(3)运动训练安静组和中等强度运动训练+力竭组大鼠MT含量显著高于安静对照组(P<0.05),且中等强度运动训练+力竭组显著高于运动训练安静组(P<0.05),一次力竭运动组大鼠MT含量显著低于安静对照组和运动训练安静组(P<0.05)。结论:运动可诱导MT合成。中等强度运动可促进心肌中MT合成适应性增加,提高心肌的抗氧化能力。     

不同力竭运动对大鼠纹状体背外侧神经元电活动的影响及调节机制研究

目的：探讨一次和重复力竭运动对纹状体背外侧神经元电活动的影响及可能的调节机制。方法：8周龄健康雄性Wistar大鼠，随机分为安静对照组（CG）、一次力竭运动组（EG）、7天重复力竭运动组（REG），每组24只，其中6只做电生理实验。采用在体多通道电生理技术记录大鼠在清醒安静状态下，一次力竭运动和7天重复力竭运动后大鼠纹状体背外侧的神经元放电活动；采用免疫荧光双染技术观察各组大鼠纹状体背外侧小青蛋白（Parvalbumin,PV）及NMDAR2B阳性神经元的表达。结果：（1）与安静状态相比，一次力竭运动后大鼠纹状体背外侧中等多棘神经元（medium spiny neuron,MSN）放电频率未发生显著改变（P>0.05），而重复力竭运动后MSN放电频率明显升高（P<0.01）;(2)一次和重复力竭运动后大鼠纹状体背外侧局部场电位γ频段的功率谱密度均较安静状态有明显增加（P<0.01），重复力竭运动后增加更为明显，且与一次力竭运动后相比有明显差异（P<0.05）;(3)一次和重复力竭运动组大鼠纹状体背外侧PV阳性神经元表达较安静对照组有显著增加（P<0.01）...     

力竭运动后大鼠海马脑区谷氨酸受体NR2A蛋白含量和基因表达的变化

目的:观察力竭运动前后大鼠脑中海马谷氨酸受体NR2A蛋白含量和基因表达的变化,探讨其与运动性疲劳的可能联系。方法:50只SD雄性大鼠,随机分为安静对照组(S,n=10),力竭运动后即刻组(AE1,n=10),力竭运动后恢复0.5小时组(AE2,n=10),力竭运动后恢复3小时组(AE3,n=10)和力竭运动后恢复24小时组(AE4,n=10)。分别采用免疫印迹法和RT-PCR法测定一次性力竭运动后大鼠脑中海马谷氨酸受体NR2A蛋白含量和基因表达。结果:与安静对照组相比,力竭运动后即刻,大鼠NR2A蛋白含量明显升高,而mRNA表达显著减少;恢复0.5小时后,蛋白含量略有下降,mRNA表达显著增加;恢复3小时后蛋白含量显著下降,mRNA表达继续增加;恢复24小时后蛋白含量恢复到安静时水平,mRNA表达则减少至恢复0.5小时后水平。结论:力竭运动后即刻及恢复过程中,大鼠脑中海马谷氨酸受体NR2A蛋白含量及mRNA表达变化趋势不同,提示基因表达对蛋白含量的调控可能具有延迟性。     

男性大学生运动疲劳前后大脑纹状体核磁共振1H谱特征分析

目的:观察运动疲劳前后大脑基底神经节纹状体1H谱物质的变化,寻找反映运动性中枢疲劳的特征物质。方法:采用磁共振氢谱检查技术,检测6名男性大学生在一次性递增负荷功率自行车运动前后脑内纹状体区域氮-乙酰天门冬氨酸(NAA)、胆碱复合物(Cho)、肌醇(mI)、α-氨基酸(α-Glx)、乳酸(Lac)以及肌酸(Cr)的含量变化并对其进行比较分析。结果:运动疲劳前后发生显著变化的特征物质包括NAA、α-Glx和Lac,其中NAA/Cr峰高较运动前显著降低(P<0.05);α-Glx/Cr峰高较运动前显著增高(P<0.05);Lac/Cr峰面积较运动前显著增加(P<0.05)。结论:运动疲劳后大脑纹状体NAA、α-Glx以及Lac水平发生变化,提示其可考虑作为运动性中枢疲劳临床诊断的参考物质。     

茜草提取物对大强度耐力训练大鼠不同组织NO-NOS体系及运动能力的影响

目的:探讨茜草提取物对大强度耐力训练大鼠不同组织NO-NOS体系酶活性及运动能力的影响。方法:24只SD大鼠随机分安静对照组、运动对照组和运动+茜草组,每组8只。运动对照组进行6周大强度跑台训练,同时运动+茜草组每天灌胃2ml剂量为0.5g/kg的茜草生理盐水溶液,安静组和训练组灌胃同体积的生理盐水。在最后一周结束后,安静组在安静时、运动对照组和运动+茜草组进行一次力竭性运动后取材,测定血清和不同组织一氧化氮(NO)含量和结构型一氧化氮合酶(cNOS)、诱导型一氧化氮合酶(iNOS)、总NOS活性。结果:运动+茜草组大鼠力竭运动时间(96.76±18.78min)显著长于运动对照组(78.95±25.47min)(P<0.05)。力竭运动后,运动对照组和运动+茜草组大鼠各组织(心脏、肝脏、脑、肾脏、股四头肌)和血清NO含量均显著高于安静对照组(P<0.01),运动+茜草组大鼠血清、心脏、脑、肾脏、股四头肌NO含量显著高于运动对照组(P<0.01,P<0.05);运动对照组大鼠心脏、肝脏、股四头肌、脑、肾脏cNOS和总NOS活性均显著低于安静对照组(P<0.05,P<0.01),iNOS活性均显著高于安静对照组(P<0.05,P<0.01);运动+茜草组大鼠心脏、肝脏、股四头肌、脑、肾脏cNOS活性显著高于运动对照组(P<0.01,P<0.05),心脏、肝脏、肾脏iNOS活性显著低于运动对照组(P<0.05),肝脏、脑、股四头肌总NOS活性显著高于运动对照组(P<0.05)。结果表明,补充茜草提取物可以调节大鼠不同组织中NOS活性,增加NO含量。     

力竭运动后大鼠海马CA1区自由基、下丘脑GABA及HPA轴的动态变化

目的:探讨运动性疲劳时神经内分泌系统的中枢调控机制。方法:50只SD大鼠随机分为安静对照组和力竭性游泳运动组,力竭组大鼠进行一次性力竭游泳运动,运动后即刻、1h、3h和24h断头取材。用放免法测定下丘脑促肾上腺激素释放激素(CRH)、血清肾上腺皮质激素(ACTH)和血清皮质酮(C);DNS-Cl荧光光度法测定下丘脑γ-氨基丁酸(GABA)含量;顺磁共振波谱法测定PBN自旋捕获剂捕获的海马CA1区自由基含量。结果:(1)力竭运动后即刻和恢复1小时组大鼠下丘脑CRH显著低于安静对照组;运动后即刻组血清ACTH浓度低于安静对照组,运动后1小时和3小时组高于安静对照组,但均无显著性差异;运动后即刻组血清C明显高于安静对照组。(2)与安静对照组相比,力竭运动后即刻、1小时和3小时组大鼠下丘脑GABA含量均显著升高。(3)与安静对照组相比,运动后即刻组大鼠海马CA1区自由基信号强度显著增强。(4)下丘脑GABA含量与下丘脑CRH呈显著负相关;海马CA1区自由基信号强度与下丘脑GABA含量呈显著正相关;海马CA1区自由基信号强度与下丘脑CRH呈显著负相关。结论:(1)下丘脑GABA可能通过直接作用于CRH神经元参与抑制运动应激时下丘脑-垂体-肾上腺皮质(HPA)轴的过度激活,并将运动疲劳时中枢的抑制状态传递到外周,使机体免受HPA轴过度激活带来的损伤。(2)力竭性运动时海马CA1区神经元自由基的增加使兴奋性增强,并可能通过Glu-GABA突触联系间接对HPA轴活性进行抑制。     

耐力训练对力竭运动诱导的大鼠淋巴细胞凋亡的影响

目的:研究耐力训练对大鼠力竭运动后淋巴细胞凋亡的影响,并分析其机制.方法:将SD大鼠随机分为安静组、力竭运动组、训练 力竭运动组.训练 力竭运动组进行3周游泳耐力训练后,除安静组外,全部大鼠负重4%进行力竭游泳,比较运动后即刻大鼠脾细胞、胸腺细胞及外周血液淋巴细胞凋亡率,细胞内Ca2 浓度及血清皮质醇(C)浓度.结果:训练 力竭运动组大鼠力竭游泳时间明显长于力竭运动组(P＜0.05);训练 力竭运动组大鼠外周血淋巴细胞凋亡率较安静组有升高趋势,但较力竭运动组有下降趋势,脾细胞凋亡率与力竭运动组相近,胸腺细胞凋亡率显著高于安静组和力竭运动组(P＜0.05);训练 力竭运动组脾细胞、外周血淋巴细胞内Ca2 浓度及血清皮质醇浓度显著高于安静组(P＜0.05);力竭运动组血清皮质醇浓度亦显著高于安静组.结论:耐力训练对力竭运动所诱导的血淋巴细胞凋亡有一定的抑制作用,对脾细胞凋亡无明显影响,还有增加胸腺细胞凋亡率的作用.耐力训练对力竭运动所诱导的血淋巴细胞及脾细胞凋亡的影响可能与阻断了细胞内Ca2 浓度及血清C水平升高所介导的细胞凋亡信号转导有关.     

运动性中枢疲劳时大鼠脑乳酸和糖原含量的变化

目的:探讨运动性中枢疲劳时大鼠脑乳酸和糖原含量的变化.方法:运用Bedford递增负荷运动方案建立运动性中枢疲劳模型.将Wistar大鼠随机分为3组:对照组、一次性力竭组和过度训练组.检测大脑皮层乳酸和糖原含量.结果:与对照组相比,一次性力竭组和过度训练组大鼠体重增加缓慢,7天分别增加13.33±7.53g和10.00±6.32g;血尿素氮分别为4.78±1.99mmol/L和8.48±0.92mmol/L,过度训练组较对照组和一次性力竭组升高明显(P<0.05);各组血红蛋白含量无明显变化.一次性力竭组和过度训练组大鼠大脑皮层5-HT含量分别为917.44±160.73ng/ml*g和730.89±392.25ng/ml*g,但无显著差异.过度训练组DA含量为309.04±63.68ng/ml*g,DA/5-HT为0.42±0.25,与对照组相比显著降低;SEP潜伏期延长,P1: 2.98±0.55ms,N1:4.23±0.35ms, P2:5.28±0.60ms.一次性力竭组脑5-HT含量、DA含量DA/5-HT及SEP潜伏期与对照组相比均无显著变化.一次性力竭组大脑皮层乳酸含量(1.12mg/100g)和过度训练组(1.46mg/100g)明显高于对照组(0.92mg/100g).各组大脑皮层糖原含量变化无显著性差异.结果提示乳酸升高和糖原耗竭可能与中枢疲劳相关联,脑乳酸蓄积可能导致中枢疲劳的发生.     

补充L-赖氨酸对急性力竭运动大鼠肾细胞凋亡及凋亡调控基因蛋白表达的影响

目的:探讨补充L-赖氨酸对急性力竭运动大鼠肾细胞凋亡及凋亡调控基因蛋白表达的影响。方法:成年雄性SD大鼠24只,随机分成3组:安静对照组、运动组和运动给药组。安静对照组不运动,运动组和运动给药组进行一次力竭运动。安静对照组和运动组在力竭运动前均灌胃一次生理盐水,而运动给药组灌胃L-赖氨酸一次。运动后即刻处死大鼠,取肾组织,HE常规染色观察细胞形态,TUNEL法检测细胞凋亡,免疫组织化学法检测bax、bcl-2和p53蛋白表达。结果:与安静对照组相比,运动组和运动给药组大鼠细胞凋亡发生率和凋亡指数显著增加(P<0.01);与运动组相比,运动给药组凋亡指数显著下降(P<0.05)。与安静对照组相比,运动组和运动给药组bax、bcl-2和p53蛋白表达的阳性细胞平均光密度值(MOD)、阳性物质表达面积和阳性指数PI差异显著增高(P<0.01,P<0.05);与运动组相比,运动给药组bax和p53显著降低,bcl-2显著增高(P<0.05)。与安静对照组相比,运动组bcl-2/bax显著降低(P<0.05),运动给药组显著增加(P<0.05);且运动给药组显著高于运动组(P<0.05)。结论:(1)一次力竭运动前补充L-赖氨酸使力竭运动诱导的肾细胞凋亡显著减少;(2)一次力竭运动前补充L-赖氨酸可使p53蛋白表达显著降低,使bcl-2蛋白表达显著增高,并使bcl-2/bax比值增高,从而起到抑制细胞凋亡的作用。     

力竭运动过程中大鼠纹状体神经元局部场电活动的动态研究

目的:探讨大鼠在安静、运动、疲劳、恢复等不同状态下纹状体神经元电活动变化特征与运动能力的关系。方法:采用金属微电极植入和在体电生理记录技术,连续动态观察一次性力竭运动过程中大鼠纹状体神经元局部场电位(LFPs)活动,并对大鼠运动能力进行观察。结果:一次性力竭运动过程中大鼠纹状体神经元LFPs活动呈动态变化规律,主要表现为:与安静状态相比,运动过程中放电频率逐渐升高、幅度逐渐降低,力竭后逐渐降低至安静水平。结论:在力竭运动过程中,纹状体LFPs活动的动态变化具有明显的阶段性特征,该脑区LFPs电活动的改变与运动疲劳有关。在运动初期纹状体主要是通过直接通路参与皮层运动的调控,而在运动后期,则主要通过间接通路发挥作用。提示:两条通路的平衡失调是导致大鼠运动能力下降的重要原因之一。     

Differentiation of exercise-induced metabolic responses during selective beta 1- and beta 2-antagonism

The effect of beta 1- or beta 2-antagonism on the plasma levels of glucose, lactate, triglycerides, and free fatty acids was studied in seventeen normal male volunteers. All subjects performed three graded and uninterrupted exercise tests until exhaustion. Prior to each exercise test they received in a randomized order during three consecutive days either placebo or a predominant beta 1-blocker (atenolol, 50 mg once per day) or a predominant beta 2-blocker (ICI 118,551, 20 mg t.i.d.), according to a double-blind cross-over study design. Atenolol increased the plasma level of glucose at rest but did not influence the rise in plasma glucose during exercise. ICI 118,551 did not change the resting plasma glucose level, but it prevented the exercise-induced rise in plasma glucose, observed during placebo. During beta 1-antagonism the plasma lactate concentration at rest and during or after exercise was not different from placebo. During beta 2-blockade the exercise-induced rise in plasma lactate tended to be suppressed, and during recovery the plasma lactate levels were significantly lower than during placebo. The serum triglycerides concentration at rest and exercise was not altered, either by beta 1- or by beta 2-antagonism. Atenolol and ICI 118,551 did not affect the serum level of free fatty acids at rest, but at moderate exercise the serum free fatty acids concentration was lower during beta 1-blockade than during placebo. Our results provide further evidence that beta 2-adrenergic receptors are involved in the regulation of the plasma levels of glucose and lactate during exercise.     

运动引起的脑与血浆亮脑啡肽变化的初步观察

<正> 脑啡肽是近年发现的一类神经调制物质—呐啡肽的一种,由中间神经元释放后作用在突触部位,在心血管、呼吸、内分泌及运动等多方面显示生理功能。脑啡肽还在肾上腺髓质嗜铬细胞内与儿茶酚胺共存并共同释放入     

Oxidation of lactate in rats after short-term strenuous exercise

Oxidation of lactate and glucose was investigated in rats after short-term strenuous running to exhaustion at a speed of 80-110 m.min-1, lasting about 100 sec. Immediately after the exercise, 4 microCi of [U-14C]lactate (LA and AR) or 9.4 microCi of [U-14C]glucose (GL) was injected into the aorta through an indwelling catheter. In AR, the rats ran at a speed of 25 m.min-1 for 20 min after injection of [U-14C]lactate. Expired gas was collected by a bottomless metabolism chamber while the rats were on the treadmill for 120 min. Blood lactate concentration tended to decrease faster in AR than in LA. Peak evolution of 14CO2 expiration occurred at 12.5 min recovery in LA, 7.5 min of recovery in AR, and 35 min of recovery in GL. Cumulative percent recovery of 14C as 14CO2 was 48.5% +/- 2.8% in LA, 74.0% +/- 2.9% in AR, and 18.6% +/- 1.6% (mean +/- SE) in GL. Significant differences were found in these rates between groups (P less than 0.01). It was suggested that a great deal of lactate was oxidized directly, not after conversion to glucose in rats after short-term strenuous exercise to exhaustion and mild exercise following strenuous exercise (active recovery) enhanced lactate oxidation.     

Dietary regimen and performance of high intensity ergometer exercise.

The influence of preceding diet (mixed, MD; carbohydrate CD; protein PD) on performance during high intensity endurance cycling was examined in six middle distance runners. Subjects undertook cycle ergometer exercise at a workload equivalent to 80% VO2 max until exhaustion following each of the three dietary regimens. Dietary analyses were performed using a computerised evaluation technique and cardiorespiratory, blood glucose and lactate responses to exercise were measured along with exercise time to exhaustion. Significant differences in carbohydrate and protein intakes were noted between respective diets as well as significantly higher total energy intake in MD (P less than 0.05). A significant relationship was observed between carbohydrate intake and exercise time to exhaustion (r = 0.59, P less than 0.05). No significant differences were noted in cardiorespiratory measures or blood glucose response after exhaustive exercise between the three dietary regimens but peak blood lactate concentration was lower following PD (P less than 0.05). Total time to exhaustion was significantly higher on CD (1070.0 +/- 106.7 s) than on PD (642.5 +/- 84.3 s, P less than 0.01). Performance time on MD (895.7 +/- 84.3 s) did not differ significantly for performance time on either CD or PD. It was concluded that dietary manipulation significantly improves exercise time to exhaustion during short term, high intensity cycling.     

Effects of acute prednisolone intake during intense submaximal exercise

To study the effects of a therapeutical dose of corticosteroid alone or associated with beta-2 agonist on performance and substrate response during intense submaximal exercise, seven healthy moderately trained male volunteers participated in the double-blind randomized cross-over study. An intense endurance exercise test to exhaustion was performed after ingestion of placebo (Pla), 20 mg prednisolone (Pred), and 20 mg prednisolone plus 4 mg salbutamol (Pred-Sal). Blood samples were collected at rest, after 5, 10 min of exercise, at exhaustion, and after 5 (r5), 10 (r10), and 20 (r20) min of passive recovery for ACTH, growth hormone, insulin, blood glucose, and lactate measurements. There were no significant differences in exercise time to exhaustion between the three treatments (Pla: 21.5 +/- 2.9; Pred: 22.0 +/- 2.5; Pred-Sal: 24.2 +/- 2.8 min). ACTH was significantly lowered after Pred and Pred-Sal vs. Pla from the start of exercise to the end of the experiment (p < 0.05). Pred and Pred-Sal increased resting and recovery (r10 and r20) significantly but not exercise blood glucose values. There were no significant differences in growth hormone concentrations between the three treatments whereas insulin was significantly higher at rest, during exercise, and at r20 after Pred-Sal administration vs. Pred and Pla (p < 0.05). Pred and Pred-Sal showed no significant effect on blood lactate compared with Pla treatment. These preliminary results do not support the hypothesis that acute oral therapeutic corticosteroid intake alone or associated with beta-2 mimetic improves performance during intense submaximal exercise, but further studies are necessary with tests of longer duration.     

Effect of hand-arm exercise on venous blood constituents during leg exercise

To test the hypothesis that ancillary arm and hand exercise would change the values of antecubital blood constituents during leg exercise, seven healthy men (19-27 yrs) performed static (10% of a maximal voluntary contraction) or dynamic (60 finger flexions/min) hand-arm exercise with one hand during submaximal leg exercise (50% V2 max) in the supine position. Venous blood was analyzed for serum Na+, K+, osmolality, albumin, total Ca2+, and glucose; blood hemoglobin, hematocrit, and lactic acid; and change in plasma volume. During leg exercise there were no significant differences in these blood constituents between right and left arms at rest. Only glucose and lactate were affected by additional arm exercise. Compared with resting arm values during leg exercise, glucose decreased from 4.7 to 4.5 mmol/l (delta = 4%, P less than 0.05) and lactate increased from 2.0 to 2.4 mmol/l (delta = 20%, P less than 0.05) during static arm exercise. With dynamic arm exercise, glucose decreased from a resting level of 4.8 to 4.7 mmol/l (delta = 2%, P less than 0.05). We conclude that additional static or dynamic hand-forearm exercise accompanying leg exercise could introduce significant errors in glucose (2%-4%) and lactic acid (6%-20%) concentrations measured in venous blood.     

Effects of short-term prednisolone intake during submaximal exercise

PURPOSE: To examine the prednisolone's ergogenic and metabolic effects during submaximal exercise. METHODS: Ten recreational male athletes completed two cycling trials at 70-75% peak O2 consumption until exhaustion after either placebo (Pla, lactose) or oral prednisolone (Pred, 60 mg.d(-1) for 1 wk) treatment, according to a double-blind and randomized protocol. Blood samples were collected at rest and during exercise and recovery to determine ACTH, growth hormone (GH), prolactin (PRL), DHEA, insulin, blood glucose, and blood lactate values. RESULTS: Time of cycling was significantly increased after chronic Pred treatment (Pred: 74.5+/-9.5 min; Pla: 46.1+/-3.3 min, P<0.01). Pred intake significantly lowered basal, exercise, and recovery ACTH, DHEA, and PRL concentrations, whereas GH concentrations were significantly lowered by Pred after 30 min of exercise. Blood glucose and insulin were significantly (P<0.05) increased by Pred during the whole experiment and until 30 min of exercise. Blood lactate concentrations were higher after Pred versus Pla at 10 min of exercise until 10 min of recovery (P<0.05). CONCLUSION: From these data, short-term Pred intake did seem to significantly improve performance during submaximal exercise, with concomitant alterations in hormonal and metabolic responses. Further studies will be necessary to elucidate the mechanisms of these hormonal and metabolic changes, and to determine whether the changes may be associated with the marked performance improvement obtained.     

力竭运动前后活体大鼠纹状体谷氨酸和γ-氨基丁酸水平的动态变化

目的:观察一次性力竭运动过程中大鼠纹状体内神经递质谷氨酸(Glu)和γ-氨基丁酸(GABA)含量及其比值的动态变化,探讨运动疲劳后纹状体神经元电活动改变的可能机制.方法:8周龄雄性Wistar大鼠8只,通过手术预先将透析套管定植入左侧纹状体(P:0.2,L:3,H:3.2).采用活体微透析与高效液相色谱(HPLC)检测...     

Blood biochemical status of miniature swine during submaximal and exhaustive exercise

Simultaneous arterial (left atrial) and mixed venous (right atrial) blood samples were anaerobically drawn from 14 miniature swine (mean weight = 25.0 +/- 1.7 [SE] kg) in order to examine the adequacy of these animals as a model for the exercising human. Samples were drawn: 1) at rest; 2) during exercise that elicited 80.4 +/- 1.2% of the animals' measured maximal heart rates; 3) at exhaustion; and 4) during the 4th min of a standing, resting recovery period. At rest, the animals were mildly alkalotic (pHa = 7.497 +/- 0.016) and hypocapnic (pCO2a = 29.6 +/- 1.2 torr), with low hematological values (arterial hemoglobin = 6.66 +/- 0.18 mmol X 1-1; arterial hematocrit = 32.0 +/- 0.9%) and slightly elevated catecholamine concentrations. During the submaximal exercise, there were no statistically significant changes in the arterial blood pH or in plasma sodium (Na+) and chloride (Cl-) concentrations, with significant decreases observed in Hcta, pCO2a, and increases in arterial plasma norepinephrine, total protein, and potassium (K+) concentrations. At exhaustion, pHa and pCO2a decreased further, with increases noted in the arterial plasma concentrations of K+, epinephrine, total protein, and the Hct but not in Na+ or Cl-. During recovery, arterial lactate averaged 20.54 +/- 0.71 mmol X 1-1. Venous changes were similar to those observed in arterial blood, with a mean pHv of 7.168 +/- 0.043 and arterial lactate = 21.08 +/- 0.90 mmol X 1-1 during recovery. Exercise-induced hemoconcentration was similar for both arterial and venous sample sites during both the submaximal and exhaustive exercise.(ABSTRACT TRUNCATED AT 250 WORDS)