title: Calcium current kinetics in young and aged human cultured myotubes.
abstract: There is evidence that the complex process of sarcopenia in human aged skeletal muscle is linked to the modification of mechanisms controlling Ca(2+) homeostasis. To further clarify this issue, we assessed the changes in the kinetics of activation and inactivation of T- and L-type Ca(2+) 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 Ca(2+) currents play a crucial role in regulating Ca(2+) entry during satellite cells differentiation and fusion into myotubes. Also, the L-type Ca(2+) channels underlie the skeletal muscle excitation-contraction coupling mechanism. Thus, our results support the hypothesis that the aging process could negatively affect the Ca(2+) homeostasis of these cells, by altering Ca(2+) entry through T- and L-type Ca(2+) channels, thereby putting a strain on the ability of human satellite cells to regenerate skeletal muscle in elderly people.
authors.affiliation: Department of Physiology and Pathology, University of Trieste, Via A. Fleming 22, I-34127 Trieste, Italy. elisaluin@dfp.units.it
authors.forename: Elisa
authors.initials: E
authors.lastname: Luin
authors.forename: Paola
authors.initials: P
authors.lastname: Lorenzon
authors.forename: Anton
authors.initials: A
authors.lastname: Wernig
authors.forename: Fabio
authors.initials: F
authors.lastname: Ruzzier
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020747:Calcium Channels, T-Type / Q000378:metabolism; D020013:Calcium Signaling; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015640:Ion Channel Gating; D007700:Kinetics; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*
chemical_list: D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type