Effects of Exercise and Glucose Supplementation on Sarcoplasmic Reticulum (SR) Ca2+-handling Properties in Human Skeletal Muscle
Notice bibliographique
Résumé
PURPOSE: In this study, we investigated the hypothesis that glucose supplementation will alter the functional characteristics of skeletal muscle SR Ca2+-handling proteins during prolonged exercise. METHODS: Fourteen untrained males cycled at ∼60% VO2peak on two occasions during which they were provided with either a no glucose placebo beverage (NG) or a 6% glucose (G) beverage (>1.00 g CHO per kg body mass). Beverages were provided starting after 30 min of exercise and every 15 min thereafter. SR Ca2+-handling properties (umol/g pro/min; SERCA activity; Ca2+-uptake [measured at 2uM]; Ca2+-release [20mM 4-CMC]) were assessed in homogenates prepared from tissue extracted from the vastus lateralis at rest, after 30 min and 90 min of exercise and at a time corresponding to fatigue during NG (115 ±6 min) in both NG and G, and at fatigue in G (137 ±7 min). RESULTS: Cycle time to fatigue was prolonged (p<0.05) during G compared to NG (137 ± 7 min vs. 115 ± 6 min). Plasma glucose (mM) was higher (p<0.05) at 90 min (5.8 ± 0.1 vs. 4.8 ± 0.2) and after 115 ± 6 min (5.6 ± 0.2 vs. 4.5 ±0.1) in G compared to NG, respectively. Exercise progressively reduced (p<0.05; Rest >30 min >90 min >115 ± 6 min and 137 ± 7 min) muscle pro and macro glycogen content in both conditions. Although exercise progressively reduced pro and macro glycogen content, no differences in glycogen content were observed at matched time points between NG and G (i.e.; 90 min, 115 ± 6 min, and 137 ± 7 min). No differences in resting SR properties (SERCA Vmax, 174 ±7 vs. 177 ± 10; Ca2+-uptake, 6.4 ± 0.3 vs 6.3 ±0.4; Phase 1 Ca2+-release, 23.4 ± 1.3 vs 23.0 ± 1.1; Phase 2 Ca2+-release, 7.3 ± 0.4 vs 7.3 ± 0.5) were observed between NG and G, respectively. Prolonged exercise reduced (p<0.05; main effect; Rest >30 min and 90 min >115 ±6 min, and 137 ±7 min) SERCA Vmax during both the G and NG conditions. During the NG ride, Vmax was depressed by 10.9 and 18.2% after 90 min of exercise and after 115 ± 6 min, respectively. During the G ride, SERCA Vmax was depressed by 7.4, 12.4 and 17.5% after 90 min, 115 ± 6 min and 137 ± 7 min, respectively. Similar exercise-induced reductions (p<0.05) were also observed for SR Ca2+-uptake and SR Ca2+-release (Phase 1 and Phase 2) kinetics during NG and G. Although exercise progressively reduced SR Ca2+-handling properties, no differences were observed at matched time points between NG and G (i.e.; 90 min, 115 ± 6 min, and 137 ± 7 min) for any SR Ca2+-handling property assessed. CONCLUSIONS: These results indicate the increase in exercise ride time during G, compared to NG, can not be explained by differences in SR Ca2+-handling properties during exercise. Funded by the Gatorade Sports Science Institute.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».