title: Mitochondrial ATP-sensitive K+ channels influence force development and anoxic contractility in a flatfish, yellowtail flounder Limanda ferruginea, but not Atlantic cod Gadus morhua heart.
abstract: The influence of ATP-sensitive K+ channels (K(ATP) channels) on cardiac performance during anoxia and reoxygenation was investigated in two species of fish showing different cardiac responses to anoxia. Force production in isometrically contracting ventricular muscle preparations from yellowtail flounder is potentiated at the onset of anoxia, while force immediately declines in Atlantic cod preparations. Glibenclamide, a general K(ATP) blocker, impaired oxygenated force development in yellowtail flounder heart but was without effect on cod preparations. The mitochondrial K(ATP) (mK(ATP))-specific blocker 5-hydroxydecanoic acid (5HD) improved oxygenated force production in yellowtail flounder heart without influencing contractility during anoxia or reoxygenation. The specific mK(ATP) agonist diazoxide preserved resting tension and eliminated anoxic force potentiation in yellowtail flounder heart preparations. Neither 5HD nor diazoxide affected contractility in cod ventricle preparations. Results indicate that K(ATP) channels can modulate contractility in yellowtail flounder heart and are potentially important in cardiac hypoxia survival in this species.
authors.affiliation: Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Newfoundland, Canada AlC 5S7.
authors.forename: Tyson J
authors.initials: TJ
authors.lastname: MacCormack
authors.forename: William R
authors.initials: WR
authors.lastname: Driedzic
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000332:Aerobiosis; D000818:Animals; D003652:Decanoic Acids / Q000494:pharmacology; D003981:Diazoxide / Q000494:pharmacology; D005399:Fishes / Q000502:physiology*; D005432:Flounder / Q000502:physiology*; D005905:Glyburide / Q000494:pharmacology; D006321:Heart / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D006880:Hydroxy Acids / Q000494:pharmacology; D000860:Hypoxia / Q000503:physiopathology*; D066298:In Vitro Techniques; D054086:KATP Channels; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D013045:Species Specificity
chemical_list: D018528:ATP-Binding Cassette Transporters; D003652:Decanoic Acids; D006880:Hydroxy Acids; D054086:KATP Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; C092520:uK-ATP-1 potassium channel; C052853:5-hydroxydecanoic acid; D003981:Diazoxide; D005905:Glyburide