Prostaglandins and the mechanism of analgesia produced by aspirin‐like drugs

Abstract

Summary . Resting splenic venous outflow from anaesthetized dogs contains prostaglandin‐like material: the concentration increases after intra‐arterial injections of bradykinin into the spleen, and is abolished by treatment with indomethacin. . Intra‐arterial injections of bradykinin into the spleen of lightly anaesthetized dogs elicit a dose‐dependent reflex increase in the blood pressure, which is reduced but not abolished by treatment with indomethacin. . Addition of prostaglandin E 1 or E 2 either by injections or by infusions restores the reflex increase in the blood pressure due to bradykinin injections after indomethacin treatment. . The sensitizing action of endogenously released prostaglandins at or near the afferent nerve endings is discussed. . The analgesic activity of aspirin‐like drugs is explained in terms of the removal of the sensitizing activity of prostaglandins.