Long lasting anti-adrenergic effect of 7-oxo-prostacyclin in the heart: a cycloheximide sensitive increase of phosphodiesterase isoform I and IV activities.

Evidence is accumulating that 7-oxo-prostacyclin (7-oxo-PGI2) induces a delayed indirect anti-adrenergic and cytoprotective effect on the myocardium, the mechanism of which is still unclear. To demonstrate that a single application of 7-oxo-PGI2 (50 micrograms/kg i.m.

In vitro effects of reactive O2 species on the beta-receptor-adenylyl cyclase system.

The irreversible loss of activity of the sarcolemma-localized beta-receptor-adenylyl cyclase system (beta-RAS) in myocardial ischemia is a well documented phenomenon. Alterations in the sarcolemma (SL) induced by reactive O2 species could be responsible for this loss. Therefore the influence of oxidation of SH-groups and lipid peroxidation induced by Fe2+/Vit.

G protein function in the ischaemic myocardium.

The activity of adenylyl cyclase (AC) is controlled by its interaction with receptor-regulated G proteins. The efficiency to form cyclic AMP is strongly influenced by the amount, the subspecies and function of these regulatory proteins. An impairment of AC function has been shown to occur in sarcolemmal preparations (SL) of hearts exposed to either local or global ischaemia.

Immunocytochemical localization of G-proteins (alpha subunits) in rat heart tissue.

The subcellular localization of peptide antibodies against G-protein alpha subunits was studied by the indirect immunogold technique with Lowicryl K4M embedded rat cardiac tissue. Two antibodies were used. The alpha common peptide antibody recognizes the alpha subunits of Gs, Gi and Go.

Free radical-induced damage of cardiac sarcolemma (SL) and activity loss of beta-receptor adenylate cyclase system (beta-RAS). A comparison of the time courses.

In vitro studies have demonstrated that free radicals generated by Fe2+/Vit. C alter the beta-RAS function. SH-oxidation, peroxidation of sarcolemmal lipids and reaction of aldehydes (formed by lipid peroxidation) with the beta-RAS may contribute to this effect.