title: Manipulation of myocardial alpha-tocopherol levels fails to affect reperfusion arrhythmias or functional recovery following ischemic challenge in the rat heart.
abstract: Antioxidants that act as free radical scavengers have the potential to inhibit lipid peroxidation. It has previously been proposed that a relationship exists between free radicals, lipid peroxidation and reperfusion-induced arrhythmias. We have therefore examined the ability of the lipid-soluble antioxidant, alpha-tocopherol, to decrease the incidence of reperfusion-induced arrhythmias. We have shown that the myocardial alpha-tocopherol content can be significantly increased from its control value of 65.3 +/- 5.6 nmoles/g wet wt of heart to 115.0 +/- 15.6 nmoles/g wet wt of heart (p less than 0.01) by chronic intraperitoneal pretreatment and that it can be decreased, to 21.1 +/- 3.7 nmoles/g wet wt of heart (p less than 0.01), by chronic dietary manipulation. Rat hearts isolated from either of these groups, or from placebo-treated control animals, were subjected to 5 or 10 min coronary artery occlusion and were subsequently reperfused; there were no significant differences between the incidence and duration of VF and VT or the incidence and number of VPBs in these three groups. The effect of alpha-tocopherol manipulation on metabolic and functional recovery of working hearts subjected to 20 min global ischemia was subsequently examined and no significant changes were observed. Cardiac output recovered to 82 +/- 4, 81 +/- 6 and 76 +/- 5% of its preischemic value in the control, enriched and depleted groups, respectively. In conclusion, myocardial alpha-tocopherol content appears to bear no relation to the severity of reperfusion-induced arrhythmias or to the resistance of the heart to ischemic injury.
authors.affiliation: Biochemistry Department, Brunel University, Uxbridge, Middlesex, England.
authors.forename: S L
authors.initials: SL
authors.lastname: Shuter
authors.forename: M
authors.initials: M
authors.lastname: Bernier
authors.forename: M J
authors.initials: MJ
authors.lastname: Davies
authors.forename: Y
authors.initials: Y
authors.lastname: Kusama
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: T F
authors.initials: TF
authors.lastname: Slater
authors.forename: D J
authors.initials: DJ
authors.lastname: Hearse
authors.forename: P B
authors.initials: PB
authors.lastname: Garlick
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control*; D002302:Cardiac Output; D003327:Coronary Disease / Q000188:drug therapy*; D003402:Creatine Kinase / Q000032:analysis; D006339:Heart Rate; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000178:diet therapy / Q000517:prevention & control*; D051381:Rats; D013997:Time Factors; D014810:Vitamin E / Q000032:analysis / Q000494:pharmacology*
chemical_list: D014810:Vitamin E; D000255:Adenosine Triphosphate; D003402:Creatine Kinase