title: Response time of mitochondrial oxygen consumption following stepwise changes in cardiac energy demand.
abstract: We determined the speed with which mitochondrial oxygen consumption and therefore the mitochondrial ATP-synthesis adapted to changes in metabolic demand in the rabbit heart. This was done by measuring the oxygen uptake of the whole heart during a stepwise change in heart rate and correcting for the time taken by diffusion and by convective transport in the blood vessels. Data for the correction for transport time were obtained from the response of venous oxygen concentration to a stepwise change of arterial oxygen concentration. The time constant of the response of mitochondrial oxygen consumption to a step change in heart rate was found to be 4-8 s.
authors.affiliation: Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: van Beek
authors.forename: N
authors.initials: N
authors.lastname: Westerhof
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D001693:Biological Transport, Active; D004734:Energy Metabolism; D006339:Heart Rate; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000378:metabolism*; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D011817:Rabbits; D012995:Solubility
chemical_list: D000255:Adenosine Triphosphate; D010100:Oxygen