Waste of ATP for tension development in myocardial acidosis: chemomechanical uncoupling at myofibrillar level.
The precise mechanism responsible for the early contractile failure after the onset of myocardial ischemia remains unclear. Physiological studies have reported that intracellular accumulation of inorganic phosphate and intracellular acidosis are the main factors of contractile failure. In contrast, biochemical experiments have shown that the Ca2+ sensitivity of myofibrillar ATPase became less as incubation pH reduces, but the maximal myofibrillar ATPase activity did not change.
Takayasu
T
T
Department of Cardiology, Jichi Medical School, Tochigi, Japan.
Toyo-oka
T
T
Hosoda
S
S
D000138:Acidosis / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003327:Coronary Disease / Q000503:physiopathology*; D006863:Hydrogen-Ion Concentration; D007537:Isometric Contraction; D009200:Myocardial Contraction; D009210:Myofibrils / Q000201:enzymology / Q000502:physiology*; D013552:Swine
D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases