Effect of physiological levels of caffeine on Ca2+ handling and fatigue development in Xenopus isolated single myofibers
- 1 May 2009
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Vol. 296 (5), R1512-R1517
- https://doi.org/10.1152/ajpregu.90901.2008
Abstract
The purpose of the present study was to determine whether exposure to exogenous physiological concentrations of caffeine influence contractility, Ca2+ handling, and fatigue development in isolated single Xenopus laevis skeletal muscle fibers. After isolation, two identical contractile periods (separated by 60-min rest) were conducted in each single myofiber ( n = 8) at 20°C. During the first contractile period, four fibers were perfused with a noncaffeinated Ringer solution, while the other four fibers were perfused with a caffeinated (70 μM) Ringer solution. The order was reversed for the second contractile period. The single myofibers were stimulated during each contractile period at increasing frequencies (0.16, 0.20, 0.25, 0.33, 0.50, and 1.0 tetanic contractions/s), with each stimulation frequency lasting 2 min until fatigue ensued, defined in this study as a fall in tension development to 66% of maximum. Tension development and free cytosolic [Ca2+] (fura-2 fluorescence spectroscopy) were simultaneously measured. There was no significant difference in the peak force generation, time to fatigue, cytosolic Ca2+ levels, or relaxation times between the noncaffeinated and caffeinated trials. These results demonstrate that physiological levels of caffeine have no significant effect on Xenopus single myofiber contractility, Ca2+ handling, and fatigue development, and suggest that any ergogenic effects of physiological levels of caffeine on muscle performance during contractions of moderate to high intensity are likely related to factors extraneous to the muscle fiber.Keywords
This publication has 50 references indexed in Scilit:
- Caffeine induces Ca2+ release by reducing the threshold for luminal Ca2+ activation of the ryanodine receptorBiochemical Journal, 2008
- The effects of caffeine ingestion on performance time, speed and power during a laboratory-based 1 km cycling time-trialJournal of Sports Sciences, 2006
- Wingate performance and surface EMG frequency variables are not affected by caffeine ingestionApplied Physiology, Nutrition, and Metabolism, 2006
- THE ACUTE EFFECTS OF A CAFFEINE-CONTAINING SUPPLEMENT ON STRENGTH,MUSCULAR ENDURANCE, AND ANAEROBIC CAPABILITIESJournal of Strength and Conditioning Research, 2006
- The Acute Effects of a Caffeine-Containing Supplement on Strength, Muscular Endurance, and Anaerobic CapabilitiesJournal of Strength and Conditioning Research, 2006
- Positive inotropism in mammalian skeletal muscle in vitro during and after fatigueCanadian Journal of Physiology and Pharmacology, 2004
- Effects of caffeine on mouse skeletal muscle power output during recovery from fatigueJournal of Applied Physiology, 2004
- Effects of modulators of sarcoplasmic Ca2+ release on the development of skeletal muscle fatigueJournal of Applied Physiology, 2004
- Potassium and caffeine contractures of mouse muscles before and after fatiguing stimulationMuscle & Nerve, 1994
- Tension restoration with caffeine in fatiguedXenopusmuscle fibres of various typesActa Physiologica Scandinavica, 1987