RELEASE OF MEDIATORS OF ANAPHYLAXIS: INHIBITION OF PROSTAGLANDIN SYNTHESIS AND THE MODIFICATION OF RELEASE OF SLOW REACTING SUBSTANCE OF ANAPHYLAXIS AND HISTAMINE

Abstract

When isolated perfused lungs from sensitized guinea‐pigs were challenged with antigen, histamine, slow reacting substance of anaphylaxis (SRS‐A) and prostaglandin‐like substances were released into the effluent. Treatment of the lungs before and during challenge with indomethacin (0.5–10 μg/ml), sodium aspirin (1–10 μg/ml), sodium meclofenamate (0.1–1 μg/ml) or ketoprofen (0.5–5 μg/ml) inhibited the release of prostaglandins while increasing the output of histamine and SRS‐A between three‐and five‐fold. Diethylcarbamazine (0.2–1 mg/ml) reduced the release of SRS‐A and histamine but increased the amount of prostaglandin‐like substances produced. Eicosatetraynoic acid (10 μg/ml) inhibited formation of prostaglandins but did not modify release of histamine and SRS‐A. The results with non‐steroid anti‐inflammatory drugs and diethylcarbamazine suggest that prostaglandins, or some other product of the cyclo‐oxygenase system, depress the anaphylactic release of SRS‐A and histamine.