title: Effect of calcium paradox on spontaneous sarcomere motions in isolated rat cardiac muscle.
abstract: Spontaneous sarcomere motions in isolated rat cardiac muscle were measured by recording the light intensity at a point of magnified muscle image. The spontaneous sarcomere motions were located near the cut end, and not evenly distributed along the muscle. Calcium depletion markedly decreased the amplitude of the light intensity fluctuations. In all cases, calcium readmission after 5 min calcium depletion (calcium paradox), which has been known to injure myocardium, increased the amplitude of the light intensity fluctuation than that under control conditions. Thus, cell injury enhances spontaneous sarcomere motions. While it remains unclear whether or not cell injury is a prerequisite for spontaneous sarcomere motions, under certain conditions the area of myocardial damage can be detected by the existence of spontaneous sarcomere motions.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D009210:Myofibrils / Q000502:physiology*; D010210:Papillary Muscles / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012518:Sarcomeres / Q000502:physiology*
chemical_list: D002118:Calcium