Cardioprotective effects of stimulation of peripheral μ-opiate receptors and the role of opiatergic mechanisms in the pathogenesis of stress-induced heart damage

Immobilization induces stress damage to the heart. DAGO, an agonist of μ-opiate receptors potentiates, while an agonist of peripheral μ-opiate receptors prevents this damage. Naltrexone reduces, while methylnaltrexone, an inhibitor of peripheral μ-opiate receptors, potentiates the stress-induced damage to the heart. Other opiate ligands have no effect on heart damage. It is suggested that the stress-induced damage to the heart is promoted by activation of central μ-opiate receptors and prevented by stimulation of peripheral μ-opiate receptors.