Functional and biochemical effects of a K(+)-ionophore on the isolated perfused rat heart.
Valinomycin, a K(+)-specific ionophore, influenced function and metabolism of isolated perfused rat hearts in a dose-dependent fashion. At a concentration of 0.05 micrograms ml-1 in perfusion fluid a 50% reduction of heart rate (HR) and a 90% reduction in max dP/dt were observed. These effects were paralleled by a substantial decrease of myocardial energy charge from about 0.80 to 0.20. A 2.5 fold increase in tissue lactate concentration indicated an increased rate of glycolytic activity. Low ATP combined with high ADP and AMP levels as found in these valinomycin-treated hearts is known to promote phosphofructokinase activity and may explain the elevated lactate levels. A significant increase in the concentrations of adenosine, IMP and inosine was observed as well.
Martinussen
H J
HJ
Department of Anaesthesiology, University Hospital, Uppsala, Sweden.
Waldenström
A
A
Ronquist
G
G
D000241:Adenosine / Q000032:analysis; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D007288:Inosine / Q000032:analysis; D007291:Inosine Monophosphate / Q000032:analysis; D007773:Lactates / Q000032:analysis / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D010477:Perfusion; D010732:Phosphofructokinase-1 / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D012212:Rheology; D014634:Valinomycin / Q000494:pharmacology*
D007773:Lactates; D007291:Inosine Monophosphate; D014634:Valinomycin; D000249:Adenosine Monophosphate; D007288:Inosine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1; D000241:Adenosine