Abstract Exercise promotes brain plasticity partly by stimulating increases in mature brain-derived neurotrophic factor (mBDNF), but the role of pro-BDNF isoform regulation BDNF metabolism humans is unknown. We quantified expression and mBDNF human skeletal muscle plasma at rest, after acute exercise (+/− lactate infusion), fasting. Pro-BDNF were analyzed with immunoblotting, enzyme-linked immunosorbent assay, immunohistochemistry, quantitative polymerase chain reaction. was consistently...

Seven subjects cycled to fatigue [75 +/- 5 (SE) min] at a work load corresponding approximately 75% of their maximal oxygen uptake. Biopsies were taken from the quadriceps femoris muscle rest and during exercise. Muscle glycogen decreased preexercise level 445 33 mmol glucosyl units/kg dry wt 50 14 fatigue. The sum measured tricarboxylic acid cycle intermediates (TCAI = malate + citrate fumarate oxaloacetate) was 0.49 0.05 mmol/kg rest, increased 4.41 0.23 after min exercise, then...

Exercise increases glucose transport into skeletal muscle via a pathway that is poorly understood. We investigated the role of endogenously produced reactive oxygen species (ROS) in contraction-mediated transport. Repeated contractions increased 2-deoxyglucose (2-DG) uptake roughly threefold isolated, mouse extensor digitorum longus (fast-twitch) muscle. N-Acetylcysteine (NAC), non-specific antioxidant, inhibited 2-DG by approximately 50% (P < 0.05 versus control values), but did not...

The sympathetic adrenergic system plays a central role in stress signalling and is often associated with increased production of reactive oxygen species (ROS). Furthermore, the intimately involved regulation cardiomyocyte Ca2+ handling contractility. In this study we hypothesize that endogenously produced ROS contribute to inotropic mechanism β-adrenergic stimulation mouse cardiomyocytes. Cytoplasmic transients, cell shortening were measured freshly isolated cardiomyocytes using confocal...

This randomized, controlled study on patients with polymyositis or dermatomyositis was based three hypotheses: display impaired endurance due to reduced aerobic capacity and muscle weakness, training improves their exercise performance by increasing the capacity, has general beneficial effects health status.In first part of this study, we compared 23 12 age- gender-matched healthy controls. A subgroup were randomized perform a 12-week program (exercise group, n = 9) non-exercising control...

To characterize splanchnic and muscle metabolism during exercise in non-insulin-dependent diabetes mellitus (NIDDM), eight male nonobese patients seven healthy control subjects (CON) were studied 40 min of bicycle at 60% maximal oxygen uptake. Biopsies obtained from the quadriceps femoris rest immediately after exercise. Arterial glucose concentration NIDDM had declined by 10% (P &lt; 0.01) end exercise, whereas CON it risen 21% 0.05). Leg uptake rose 0.19 +/- 0.06 mmol/min to 2.25 0.61 0.13...

Skeletal muscle often shows a delayed force recovery after fatiguing stimulation, especially at low stimulation frequencies. In this study we focus on the role of reactive oxygen species (ROS) in fatigue‐induced prolonged low‐frequency depression. Intact, single fibres were dissected from flexor digitorum brevis (FDB) muscles rats and wild‐type superoxide dismutase 2 (SOD2) overexpressing mice. Force myoplasmic free [Ca 2+ ] ([Ca i ) measured. Fibres stimulated different frequencies before...

Summary. The effect of dynamic exercise on muscle and blood ammonia (NH 3 ) amino acid contents has been investigated. Eight healthy men cycled at 50% 97% maximal oxygen uptake for 10 min 5·2 (to fatigue), respectively. Biopsies (quadriceps femoris muscle), arterial femoral venous samples were obtained rest during exercise. Muscle NH after submaximal was ( x̄ ±SE) 0·5±0·1 mmol/kg dry (d.m.) increased to 4·1 ±0·5 d.m. fatigue P &lt;0·001). total adenine nucleotide (TAN) pool (TAN=ATP+ADP+AMP)...

Obesity and insulin resistance are associated with enhanced fatty acid utilization, which may play a central role in diabetic cardiomyopathy. We now assess the effect of saturated palmitate (1.2 mmol/l) on Ca(2+) handling, cell shortening, mitochondrial production reactive oxygen species (ROS) freshly isolated ventricular cardiomyocytes from normal (wild-type) obese, insulin-resistant ob/ob mice. Cardiomyocytes were electrically stimulated at 1 Hz, signal fluorescent indicators was measured...

Increased myoplasmic inorganic phosphate (P i ) has been suggested to have an important role in skeletal muscle fatigue, especially the early phase. In present study we used intact fast‐twitch cells from mice completely deficient creatine kinase (CK ‐/‐ test this suggestion. These CK provide a good model since they display higher P concentration unfatigued state and fatigue without significant increase of . Tetanic contractions (350 ms duration) were produced single fibres. The free [Ca 2+ ]...

Isolated whole skeletal muscles fatigue more rapidly than isolated single muscle fibres. We have now employed this difference to study mechanisms of fatigue. soleus and extensor digitorum longus (EDL) were fatigued by repeated tetanic stimulation while measuring force production. Neither application 10 m lactic acid nor increasing the [K + ] bath solution from 5 had any significant effect on rate decline during induced brief tetani. Soleus slightly faster continuous in ]. Inhibition...

The involvement of Ca(2+) in insulin-mediated glucose uptake is uncertain. We measured influx (as Mn(2+) quenching or Ba(2+) influx) and 2-deoxyglucose (2-DG) single muscle fibers isolated from limbs adult mice; 2-DG was also whole muscles. Exposure to insulin increased the cells. presence decreased by 2-aminoethoxydiphenyl borate (2-APB) membrane-permeable diacylglycerol analog 1-oleyl-2-acetyl-sn-glycerol (OAG), agents frequently used block activate, respectively, nonselective cation...

It has been recently suggested that high glucose infusion rates during euglycemic hyperinsulinemia result in accumulation of free human skeletal muscle (J. Clin. Invest. 76: 357, 1985). To examine this possibility, we performed a euglycemic, hyperinsulinemic clamp together with biopsies from the quadriceps femoris on seven healthy men. Insulin was infused at successive 40 and 400 mU. m-2.min-1, resulting mean plasma insulin concentrations 69 +/- 3 1,285 115 (SE) microU/ml, respectively....

Mammals exposed to a cold environment initially generate heat by repetitive muscle activity (shivering). Shivering is successively replaced the recruitment of uncoupling protein-1 (UCP1)-dependent production in brown adipose tissue. Interestingly, adaptations observed skeletal muscles cold-exposed animals are similar those with endurance training. We hypothesized that increased myoplasmic free [Ca2+] ([Ca2+]i) important for these adaptations. To test this hypothesis, experiments were...

Consumption of L-arginine contributes to reduced bioavailability nitric oxide (NO) that is critical for the development ischemia-reperfusion injury. The aim study was determine myocardial arginase expression and activity in ischemic-reperfusion myocardium whether local inhibition within ischemic results increased NO production protection against ischemia-reperfusion. Anesthetized pigs were subjected coronary artery occlusion 40 min followed by 4 h reperfusion. randomized intracoronary...

The effect of bicycle exercise (75% maximal oxygen uptake) on glucose uptake by the inferior limb (LGU) and glycolysis in human skeletal muscle has been investigated. Biopsies were obtained from quadriceps femoris before exercise, after 5 40 min at fatigue [74.9 +/- 4.7 (SE) min]. LGU was 0.05 0.02 mmol/min rest, increased approximately sevenfold continued to increase linearly during first exercise. Thereafter stabilized 1.4 until fatigue. Intracellular low rest but sixfold (P less than 0.01...

Blood glutathione status and activities of antioxidant enzymes have been investigated during prolonged exercise with or without carbohydrate (CHO) supplementation. Eight subjects cycled at approximately 70% maximal oxygen uptake to fatigue [134 +/- 19 (SE) min] on the first occasion (control, CON) same work load duration second but CHO ingestion exercise. reduced (GSH) concentration increased from 0.55 0.05 mM rest 0.77 0.09 after 120 min CON (P &lt; 0.01) remained constant disulfide (GSSG)...

Obesity, insulin resistance, and type 2 diabetes are leading causes of heart failure, defective cellular Ca2+ handling seems to be a fundamental problem in diabetes. Therefore, we studied the effect on homeostasis normal, freshly isolated mouse ventricular cardiomyocytes whether was changed an animal model obesity diabetes, ob/ob mice. Electrically evoked transients were smaller slower compared with wild-type cardiomyocytes. Application (6 or 60 nmol/l) increased amplitude cells by ∼30%,...

The involvement of Ca(2+) in the insulin-mediated signaling cascade, resulting glucose uptake skeletal muscle, is uncertain. Here, we test hypothesis that influx through canonical transient receptor potential 3 (TRPC3) channels modulates adult muscle. Experiments were performed on muscle cells wild-type (WT) and obese, insulin-resistant ob/ob mice. Application diacylglycerol analog 1-oleyl-2-acetyl-sn-glycerol (OAG) induced a nonselective cation current, which was inhibited by addition...