A5068466904- Muscle Physiology and Disorders
- Muscle activation and electromyography studies
- Exercise and Physiological Responses
- Cardiomyopathy and Myosin Studies
- Cardiovascular and exercise physiology
- Adipose Tissue and Metabolism
- Ion channel regulation and function
- Sports Performance and Training
- Muscle metabolism and nutrition
- Mitochondrial Function and Pathology
- Neuroscience and Neural Engineering
- Cardiovascular Effects of Exercise
- Metabolism, Diabetes, and Cancer
- Genetic Neurodegenerative Diseases
- Cardiac electrophysiology and arrhythmias
- Metabolism and Genetic Disorders
- Genetics and Physical Performance
- Advanced Sensor and Energy Harvesting Materials
- Neurobiology and Insect Physiology Research
- Nitric Oxide and Endothelin Effects
- Ion Channels and Receptors
- Cellular Mechanics and Interactions
- Calcium signaling and nucleotide metabolism
- Inflammatory Myopathies and Dermatomyositis
- Glycogen Storage Diseases and Myoclonus
Karolinska Institutet
2015-2024
Lithuanian Sports University
2015-2024
Mid Sweden University
2015
University of Lausanne
2015
Karolinska University Hospital
1989-2012
University of Oslo
2001-2006
Institutt for Eksperimentell Medisinsk Forskning
2001-2006
Institute for Molecular Medicine
2002
Baylor College of Medicine
2002
The University of Sydney
1990-1996
We used intact single fibres from a mouse foot muscle to study the role of oxidation‐reduction in modulation contractile function. The oxidant hydrogen peroxide (H 2 O , 100‐300 μM) for brief periods did not change myoplasmic Ca 2+ concentrations ([Ca ] i ) during submaximal tetani. However, force increased by 27 % same contractions. effects H were time dependent. Prolonged exposures resulted resting and tetanic [Ca while was significantly diminished. decline mainly due reduced myofibrillar...
Measurements of the intracellular free concentration Ca2+ ([Ca2+]i) were performed during fatiguing stimulation intact, single muscle fibers, which dissected from a mouse foot and loaded with fura-2. Fatigue, was produced by repeated 100-Hz tetani, generally occurred in three phases. Initially, tension declined rapidly to approximately 90% original (0.9 Po) this period tetanic [Ca2+]i increased significantly (phase 1). Then followed lengthy almost stable production 2). Finally, both fell...
Key points Dietary supplementation with inorganic nitrate has beneficial effects on skeletal muscle responses to exercise. Both mitochondrial and extra‐mitochondrial explanations have been proposed. Contractile force of fast‐twitch muscles was enhanced in mice supplemented 1 m NaNO 3 drinking water for 7 days. Myoplasmic free [Ca 2+ ] during tetanic stimulation increased nitrate‐supplemented this accompanied by expression calsequestrin the dihydropyridine receptor. These results provide a...
The respiratory and limb skeletal muscles become weakened in sepsis, congestive heart failure, other inflammatory diseases. A potential mediator of muscle weakness is tumor necrosis factor (TNF)-α, a cytokine that can stimulate wasting also induce contractile dysfunction without overt catabolism. This study addressed the latter process. Murine diaphragm (flexor digitorum brevis [FDB]) preparations were used to determine relative sensitivities these TNF-α. Intact fibers isolated from FDB...
We have generated an animal model for mitochondrial myopathy by disrupting the gene transcription factor A (Tfam) in skeletal muscle of mouse. The knockout animals developed a with ragged-red fibers, accumulation abnormally appearing mitochondria, and progressively deteriorating respiratory chain function muscle. Enzyme histochemistry, electron micrographs, citrate synthase activity revealed substantial increase mass mice. Biochemical assays demonstrated that increased partly compensated...
Low-frequency fatigue is a form of muscle that follows intense activity and characterized by reduced tetanic tension at low frequencies stimulation while high stimulus close to normal. The present experiments were performed on isolated single fibers mouse in which intracellular calcium concentration ([Ca2+]i) measured. Fatigue was produced intermittent short tetani continued until had declined 30% control. Comparison low- (30- 50-Hz) high- (100-Hz) frequency under control conditions after 30...
1. The effect of altered intracellular pH (pHi) on isometric contractions and shortening velocity at 12, 22 32 degrees C was studied in intact, single fibres mouse skeletal muscle. Changes pHi were obtained by exposing to solutions with different CO2 concentrations. 2. Under control conditions (5% CO2), (measured carboxy SNARF‐1) about 0.3 units more alkaline than neutral water each temperature. An acidification 0.5 produced 30% an alkalinization similar size 0% CO2. 3. In acidified tetanic...
1. Single muscle fibres were dissected from Xenopus lumbrical muscles and microinjected with the photoprotein aequorin in order to measure myoplasmic free calcium concentration ([Ca2+]i). Fatigue was produced by repeated intermittent tetanic stimulation continued until tension had declined approximately 50% of initial level. Fibres then allowed recover giving tetani at less frequent intervals. Aequorin light (a [Ca2+]i) measured during fatiguing recovery. 2. During stimulation, steadily, but...
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...
Significance High-intensity interval training (HIIT) has become popular because it is a time-efficient way to increase endurance. An intriguing and so-far-unanswered question how few minutes of HIIT can be that effective. We exposed recreationally active men one session three six sets 30-s high-intensity cycling exercise. Muscle biopsies taken 24 h later showed an extensive fragmentation the sarcoplasmic reticulum (SR) Ca 2+ channels, ryanodine receptor 1 (RyR1). In isolated mouse muscle...
Physical exercise has emerged as an alternative treatment for patients with depressive disorder. Recent animal studies show that protects from depression by increased skeletal muscle kynurenine aminotransferase (KAT) expression which shifts the metabolism away neurotoxic (KYN) to production of kynurenic acid (KYNA). In present study, we investigated effect on in humans. KAT gene and protein was muscles endurance-trained subjects compared untrained subjects. Endurance caused increase plasma...
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...