Mechanism of noradrenaline potentiation by prostaglandin E2 in rat mesenteric artery.
1 Effects of prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha) on vasoconstrictor responses to noradrenaline (NA) and methoxamine in isolated mesenteric arteries of the rat were investigated. 2 PGE2 and to a lesser extent PGF2 alpha potentiated vasoconstrictor responses to NA and methoxamine. 3 Prior treatment with reserpine increased, and bretylium reduced, the extent of potentiation significantly. 4 NA vasoconstriction persisted for 1 h after Ca2+ was removed from the perfusing Krebs solution. Prostaglandin-induced potentiation was absent in Ca2+-free Krebs, but increased proportionately with increase in external Ca2+ concentration. 5 Vasoconstriction induced by high potassium, was not potentiated by PGE2. 6 It is concluded the PGE2 potentiates NA vasoconstriction by facilitating Ca2+ influx.
D000818:Animals; D004357:Drug Synergism; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D008729:Methoxamine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism; D011458:Prostaglandins E / Q000494:pharmacology*; D011652:Pulmonary Circulation / Q000187:drug effects; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
D011453:Prostaglandins; D011458:Prostaglandins E; D012110:Reserpine; D008729:Methoxamine; D011188:Potassium; D009638:Norepinephrine