title: Stability of membrane potential in heart mitochondria: single mitochondrion imaging.
abstract: Mitochondrial membrane potential (delta psi(m)) plays an important role in cellular activity. Although delta psi(m) of intracellular mitochondria are relatively stable, the recent experiments with isolated mitochondria demonstrate that individual mitochondria show frequent fluctuations of delta psi(m). The current study is performed to investigate the factors that stabilize delta psi(m) in cells by observing delta psi(m) of individual isolated mitochondria with fluorescence microscopy. Here, we report that (1) the transient depolarizations are also induced for mitochondria in plasma membrane permeabilized cells, (2) almost all mitochondria isolated from porcine hearts show the transient depolarizations that is enhanced with the net efflux of protons from the matrix to the intermembrane space, and (3) ATP and ADP significantly inhibit the transient depolarizations by plural mechanisms. These results suggest that the suppression of acute alkalinization of the matrix together with the presence of ATP and ADP contributes to the stabilization of delta psi(m) in cells.
authors.affiliation: Division of Biotechnology and Life Science, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, Nakacho, Koganei, Tokyo 184-8588, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Uechi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yoshioka
authors.forename: Daisuke
authors.initials: D
authors.lastname: Morikawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ohta
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D008293:Malates / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009249:NADP / Q000378:metabolism; D009840:Oligomycins / Q000494:pharmacology; D051381:Rats; D012402:Rotenone / Q000494:pharmacology; D019802:Succinic Acid / Q000494:pharmacology; D013552:Swine
chemical_list: D008293:Malates; D009840:Oligomycins; D012402:Rotenone; D009249:NADP; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000244:Adenosine Diphosphate; C030298:malic acid; D000255:Adenosine Triphosphate; D019802:Succinic Acid