Calcium currents and transients in co-cultured contracting normal and Duchenne muscular dystrophy human myotubes

Autor: Nathalie Imbert, Christian Cognard, Bruno Constantin, Clarisse Vandebrouck, Guy Raymond, Michael J. Cullen, Gérard Duport, Abdul A. Hassoni
Přispěvatelé: Institut de physiologie et biologie cellulaires (IPBC), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2001
Předmět:
Patch-Clamp Techniques
Physiology
[SDV]Life Sciences [q-bio]
Muscle Fibers
Skeletal
chemistry.chemical_element
[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC]
Calcium
Calcium in biology
Membrane Potentials
03 medical and health sciences
0302 clinical medicine
Ganglia
Spinal
medicine
[SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO]
Animals
Homeostasis
Humans
Patch clamp
Muscle
Skeletal
Cells
Cultured
030304 developmental biology
Calcium metabolism
Membrane potential
0303 health sciences
Voltage-dependent calcium channel
Myogenesis
Anatomy
Original Articles
Coculture Techniques
Rats
Muscular Dystrophy
Duchenne
Microscopy
Electron
chemistry
Spinal Cord
Biophysics
Calcium Channels
medicine.symptom
030217 neurology & neurosurgery
[SDV.MHEP]Life Sciences [q-bio]/Human health and pathology
Muscle contraction
Muscle Contraction
Zdroj: The Journal of Physiology
The Journal of Physiology, Wiley, 2001, 534 (2), pp.343-355. ⟨10.1111/j.1469-7793.2001.00343.x⟩
ISSN: 0022-3751
1469-7793
DOI: 10.1111/j.1469-7793.2001.00343.x⟩
Popis: International audience; 1. The goal of the present study was to investigate differences in calcium movements between normal and Duchenne muscular dystrophy (DMD) human contracting myotubes co-cultured with explants of rat spinal cord with attached dorsal root ganglia. Membrane potential, variations of intracellular calcium concentration and T- and L-type calcium currents were recorded. Further, a descriptive and quantitative study by electron microscopy of the ultrastructure of the co-cultures was carried out. 2. The resting membrane potential was slightly less negative in DMD (-61.4 +/- 1.1 mV) than in normal myotubes (-65.5 +/- 0.9 mV). Both types of myotube displayed spontaneous action potentials (mean firing frequency, 0.42 and 0.16 Hz, respectively), which triggered spontaneous calcium transients measured with Indo-1. 3. The time integral under the spontaneous Ca(2+) transients was significantly greater in DMD myotubes (97 +/- 8 nM s) than in normal myotubes (67 +/- 13 nM s). 4. The L- and T-type current densities estimated from patch-clamp recordings were smaller in DMD cells (2.0 +/- 0.5 and 0.90 +/- 0.19 pA pF(-1), respectively) than in normal cells (3.9 +/- 0.7 and 1.39 +/- 0.30 pA pF(-1), respectively). 5. The voltage-dependent inactivation relationships revealed a shift in the conditioning potential at which inactivation is half-maximal (V(h,0.5)) of the T- and L-type currents towards less negative potentials, from -72.1 +/- 0.7 and -53.7 +/- 1.5 mV in normal cells to -61.9 +/- 1.4 and -29.2 +/- 1.4 mV in DMD cells, respectively. 6. Both descriptive and quantitative studies by electron microscopy suggested a more advanced development of DMD myotubes as compared to normal ones. This conclusion was supported by the significantly larger capacitance of the DMD myotubes (408 +/- 45 pF) than of the normal myotubes (299 +/- 34 pF) of the same apparent size. 7. Taken together, these results show that differences in T- and L-type calcium currents between normal and DMD myotubes cannot simply explain all observed alterations in calcium homeostasis in DMD myotubes, thus suggesting that other transmembrane calcium transport mechanisms must also be altered in DMD myotubes compared with normal myotubes.
Databáze: OpenAIRE
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