Mitochondrial K(ATP) channels and sarcoplasmic reticulum influence cardiac force development under anoxia in the Amazonian armored catfish Liposarcus pardalis.
The contribution of alterations in mitochondrial K(ATP) channel activity and the sarcoplasmic reticulum (SR) to anaerobic cardiac function in the anoxia tolerant armored catfish Liposarcus pardalis were assessed. K(ATP) channels contribute to hypoxic cardioprotection in mammals, but little is known of their action in more hypoxia tolerant animals. Anoxia resulted in a decrease in force in isometrically contracting ventricle strips to approximately 40% of the pre-anoxic level. This was maintained for at least 2 h. Upon reoxygenation, hearts recovered to the same level as control preparations. Treatment with 5-hydroxydecanoic acid (5HD), a specific mitochondrial K(ATP) blocker significantly increased force in preparations during anoxia and caused hypercontracture at reoxygenation. Ryanodine, a specific inhibitor of SR function, significantly increased force loss in ventricle preparations under anoxia. Results show that mitochondrial K(ATP) channel activity and SR function are important in anaerobic and post-anaerobic contractility in armored catfish heart.
MacCormack
Tyson J
TJ
Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, A1C 5S7, Newfoundland, Canada.
Treberg
Jason R
JR
Almeida-Val
Vera M F
VM
Val
Adalberto L
AL
Driedzic
Willam R
WR
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002397:Catfishes / Q000378:metabolism / Q000502:physiology*; D003652:Decanoic Acids / Q000494:pharmacology; D006880:Hydroxy Acids / Q000494:pharmacology; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000502:physiology*
D003652:Decanoic Acids; D006880:Hydroxy Acids; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D012433:Ryanodine; C052853:5-hydroxydecanoic acid; D000255:Adenosine Triphosphate; D010100:Oxygen