Intracellular Ca2+-handling differs markedly between intact human muscle fibers and myotubes

Background In skeletal muscle, intracellular Ca2+ is an important regulator of contraction as well as gene expression and metabolic processes. Because of the difficulties to obtain intact human muscle fibers, human myotubes have been extensively employed for studies of Ca2+-dependent processes in human adult muscle. Despite this, it is unknown whether the Ca2+-handling properties of myotubes adequately represent those of adult muscle fibers.