The fatiguing effect of a series of isometric tetani and of tetani with shortening and maximum power output were compared using soleus and extensor digitorum longus muscle of mouse. Mean force in test isometric tetani after the series was reduced by up to 35% compared with pre-series controls. Tetani with shortening were always more fatiguing than isometric tetani.
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http://dx.doi.org/10.1113/expphysiol.1989.sp003367 | DOI Listing |
Clin Pediatr Endocrinol
March 2024
Department of Pediatrics, Dokkyo Medical University, Tochigi 321-0293, Japan.
J Physiol
July 2024
Institute for Experimental Medical Research, University of Oslo and Oslo University Hospital, Oslo, Norway.
Large trans-sarcolemmal ionic shifts occur with fatiguing exercise or stimulation of isolated muscles. However, it is unknown how resting membrane potential (E) and intracellular sodium concentration ([Na]) change with repeated contractions in living mammals. We investigated (i) whether [Na] (peak, kinetics) can reveal changes of Na-K pump activity during brief or fatiguing stimulation and (ii) how resting E and [Na] change during fatigue and recovery of rat soleus muscle in situ.
View Article and Find Full Text PDFNephrology (Carlton)
March 2024
Department of Pediatrics, Ome Municipal General Hospital, Ome, Japan.
J Physiol
December 2023
Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Ontario, Canada.
A reduced muscle glycogen content and potassium (K ) disturbances across muscle membranes occur concomitantly during repeated intense exercise and together may contribute to skeletal muscle fatigue. Therefore, we examined whether raised extracellular K concentration ([K ] ) (4 to 11 mM) interacts with lowered glycogen to reduce force production. Isometric contractions were evoked in isolated mouse soleus muscles (37°C) using direct supramaximal field stimulation.
View Article and Find Full Text PDFJ Neurol Sci
November 2023
Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, USA. Electronic address:
The World Meteorological Organization considers a heatwave as "a period of statistically unusual hot weather persisting for a number of days and nights". Accompanying the ongoing global climate change, sharp heatwave bouts occur worldwide, growing in frequency and intensity, and beginning earlier in the season. Heatwaves exacerbate the risk of heat-related illnesses, hence human morbidity and mortality, particularly in vulnerable elderly and children.
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