Calcium current kinetics in young and aged human cultured myotubes |
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Authors: | Luin Elisa Lorenzon Paola Wernig Anton Ruzzier Fabio |
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Affiliation: | aDepartment of Physiology and Pathology, University of Trieste, Via A. Fleming 22, I-34127 Trieste, Italy;bDepartment of Physiology, University of Bonn, Wilhelmstrasse 31, D-53111 Bonn, Germany |
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Abstract: | There is evidence that the complex process of sarcopenia in human aged skeletal muscle is linked to the modification of mechanisms controlling Ca2+ homeostasis. To further clarify this issue, we assessed the changes in the kinetics of activation and inactivation of T- and L-type Ca2+ currents in in vitro differentiated human myotubes, derived from satellite cells of healthy donors aged 2, 12, 76 and 86 years. The results showed an age-related decrease in the occurrence of T- and L-type currents. Moreover, significant age-dependent alterations were found in L-(but not T) type current density, and activation and inactivation kinetics, although an interesting alteration in the kinetics of T-current inactivation was observed. The T- and L-type Ca2+ currents play a crucial role in regulating Ca2+ entry during satellite cells differentiation and fusion into myotubes. Also, the L-type Ca2+ channels underlie the skeletal muscle excitation–contraction coupling mechanism. Thus, our results support the hypothesis that the aging process could negatively affect the Ca2+ homeostasis of these cells, by altering Ca2+ entry through T- and L-type Ca2+ channels, thereby putting a strain on the ability of human satellite cells to regenerate skeletal muscle in elderly people. |
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Keywords: | Human satellite cells Skeletal muscle aging Ca2+ homeostasis T-type Ca2+ channels L-type Ca2+ channels |
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