Regulation of prostaglandin receptors in myocardial ischemia.
Sarcolemmal membranes from pig hearts express a homogenous class of binding sites for [3H]PGE1. Competition binding studies with EP receptor suptype selective ligands suggest an EP3 receptor subtype. The GTP analogue GTP gamma S reduced affinity without changing binding capacity, indicating a G protein coupled EP3 receptor. Regional myocardial ischemia (60 min) in anesthetized, open-chest pigs caused a 50% increase of the number of binding sites while GTP gamma S still decreased [3H]PGE1 binding, suggesting intact G protein coupling. Myocardial ischemia may, therefore, modify myocardial actions of prostaglandins.
Hohlfeld
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Institut für Pharmakologie, Universität Düsseldorf, FRG.
D000818:Animals; D019204:GTP-Binding Proteins / Q000378:metabolism; D017202:Myocardial Ischemia / Q000378:metabolism*; D011982:Receptors, Prostaglandin / Q000378:metabolism*; D015424:Reperfusion; D012508:Sarcolemma / Q000378:metabolism*; D013552:Swine
D011982:Receptors, Prostaglandin; D019204:GTP-Binding Proteins