Limitation of stunning in dog myocardium by nucleoside and nucleotide mixture, OG-VI.
BACKGROUND
OG-VI is a nucleoside-nucleotide solution composed of 30 mM inosine, 30 mM cytidine, 30 mM sodium 5'-guanylate, 22.5 mM uridine, and 7.4 mM thymidine. It is expected to enhance the efficacy of intravenous hyperalimentation in surgically stressed patients. One of the main causes of ischemic myocardial damage is loss of adenine nucleotides from heart cells. The aim of the present study, therefore, was to examine the effect of OG-VI on myocardial mechanical function and energy metabolism in stunned myocardium.


METHODS
Pentobarbital-anesthetized dogs were subjected to 20 min ligation of the left anterior descending (LAD) coronary artery, followed by reperfusion for 30 min. OG-VI at 0.1 or 0.2 ml/kg/min or saline was infused from the left femoral vein throughout the experiment. The tissue levels of high-energy phosphates in the hearts were determined after 30 min reperfusion.


RESULTS
LAD flow, first derivative of left ventricular pressure (LVdp/dt), and segment function were increased by OG-VI in a dose-dependent manner. OG-VI infusion resulted in a significant improvement in LVdP/dt and segment shortening in the ischemic/reperfused myocardium compared with saline infusion. The levels of segment shortening with saline, 0.1, and 0.2 ml/kg/min OG-VI after reperfusion for 30 min were -0.3, 75, and 82% of the preligation levels, respectively. The tissue level of adenosine triphosphate (ATP) after reperfusion in OG-VI-infused animals was significantly higher than that in saline-infused animals.


CONCLUSIONS
OG-VI has a positive inotropic action, and its infusion results in a marked cardioprotective effect in stunned myocardium associated with the restoration of tissue ATP level.
Satoh
K
K
Department of Pharmacology, Hokkaido College of Pharmacy, Otaru, Japan.
Nakai
T
T
Hoshi
K
K
Ichihara
K
K
D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004285:Dogs; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics; D008297:Male; D017682:Myocardial Stunning / Q000188:drug therapy* / Q000503:physiopathology; D009705:Nucleosides / Q000494:pharmacology* / Q000627:therapeutic use; D009711:Nucleotides / Q000494:pharmacology* / Q000627:therapeutic use
D002316:Cardiotonic Agents; D009705:Nucleosides; D009711:Nucleotides; C087081:OG-VI solution