Free radical scavenging enzymes and G protein mediated receptor signalling systems in ischaemically preconditioned porcine myocardium.

• OBJECTIVE: Increased antioxidant defence and altered G protein mediated receptor signalling systems could be expected in myocardial preconditioning. The myocardial antioxidant defence and the integrity of the G protein mediated receptor signalling systems were therefore examined in normal and preconditioned myocardium. METHODS: Preconditioning in the porcine heart was induced by two occlusions of the mid left anterior descending coronary artery for 10 min, with a 30 min reperfusion interval. Left ventricular biopsies were obtained from control and preconditioned regions 30 min after the last occlusion. RESULTS: In biopsies from the preconditioning region, neither the activities of superoxide dismutase of glutathione peroxidase, nor the content of malondialdehyde were changed. There were no alterations in either the number of receptors (beta adrenergic, muscarinic and endothelin receptors) or the amount of G proteins. Furthermore, the activity of adenylyl cyclase remained unchanged. CONCLUSIONS: No change in the antioxidant defence was demonstrated in preconditioned myocardium. This finding does not support the hypothesis that increased antioxidant defence could contribute to the cardioprotection of preconditioning. Additionally, an intact G protein mediated receptor signalling system was found in preconditioned myocardium with regard to beta adrenergic, muscarinic, and endothelin receptors.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Animals

Disease Models

Animal

Female

Free Radical Scavengers

GTP-Binding Proteins

metabolism

Male

Myocardial Infarction

prevention & control

Myocardial Ischemia

enzymology

metabolism

Myocardial Reperfusion

Myocardial Reperfusion Injury

prevention & control

Myocardium

enzymology

metabolism

Receptors

Adrenergic

beta

metabolism

Receptors

Cell Surface

metabolism

Receptors

Endothelin

metabolism

Receptors

Muscarinic

metabolism

Signal Transduction

physiology

Swine

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)