Fura-2 imaging of spontaneous and electrically induced oscillations of intracellular free Ca2+ in rat myotubes
| Autor: | Jacqueline Chapron, Philippe Méléard, Marie Laure Lascombe, Michel Grouselle, Jeanine Koenig, D. Georgescauld |
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| Rok vydání: | 1991 |
| Předmět: |
medicine.medical_specialty
Contraction (grammar) Fura-2 Physiology Clinical Biochemistry chemistry.chemical_element Calcium Biology chemistry.chemical_compound Physiology (medical) Internal medicine Caffeine medicine Animals Cells Cultured Myogenesis Endoplasmic reticulum Muscles Electric Stimulation Rats Cytosol Membrane Endocrinology chemistry Biophysics Intracellular Cadmium |
| Zdroj: | Pflugers Archiv : European journal of physiology. 418(1-2) |
| ISSN: | 0031-6768 |
| Popis: | Rat myotubes have a resting [Ca2+]i of about 82 nM. Myotubes 3-5 days old (quiescent myotubes) display electrically induced and spontaneous transients in the intracellular concentration of free Ca2+ ions ([Ca2+]i) uncoupled to any detectable contraction. By contrast, 1- to 2-day-old myotubes are insensitive to electrical stimuli and, after 6 days in culture, stimulated myotubes always show [Ca2+]i transients and twitch contractions. The spatial distribution of [Ca2+]i variations in quiescent myotubes is heterogeneous, local increases in [Ca2+]i being mainly observed near the periphery of the cell. The small effect of different external Ca2+ concentrations and of Cd2+ on the amplitude of the [Ca2+]i oscillation indicates that the main source of Ca2+ may be the sarcoplasmic reticulum. This conclusion is supported by the close similarity between electrically induced and caffeine-induced [Ca2+]i maps. These findings suggest that, at an early stage of myotube ontogenesis, a part of the excitation/contraction coupling, as membrane ionic channels, voltage sensors and Ca2+ release and reuptake mechanisms, is functional but, apparently, still uncoupled to the contractile machinery. |
| Databáze: | OpenAIRE |
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