Pretreatment with coenzyme Q10 protects guinea pig ventricular muscle from hypoxia-induced deterioration of action potentials and contraction.

Effects of coenzyme Q10 (CoQ10) on hypoxia-induced changes in transmembrane action potentials and isometric tension were studied in isolated guinea pig ventricular papillary muscles. Guinea pigs were pretreated with CoQ10 (60 mg/kg/day i.p., n = 4) or the solvent (n = 4) for 3 consecutive days before the study. The hypoxia for 30 min (Po2 = 40 mmHg) was induced to the preparation twice with a 20 min normoxic perfusion (Po2 = 300 mmHg) intervention. The hypoxia markedly shortened action potential duration (APD) and decreased the developed tension, the effects being more pronounced during the second than the first-induced hypoxia. Pretreatment with CoQ10 or the solvent did not affect the membrane potentials and contractile tension under normoxic conditions. The decreases in APD and the developed tension produced by hypoxia were partially but significantly suppressed in the preparation obtained from CoQ10-pretreated animals. The results suggest that the pretreatment with CoQ10 partially protects the isolated ventricular muscle subjected to hypoxia from the deterioration of action potentials and contraction.