[Effects of anti-inflammatory drugs on the arachidonic acid induced erythema in guinea pigs (author's transl)].

The inhibitory effects of anti-inflammatory drugs on th erythema induced by arachidonic acid in guinea pigs were studied. Values of ED50 (mg/kg, p.o.) were; diclofenac sodium (19.9), indomethacin (28.1), naproxen (52.4), phenylbutazone (67.1), ibuprofen (81.3), aspirin (92.6). These drugs, however, were ineffective on the erythema induced by prostaglandin E2. Basic nonsteroidal and steroidal anti-inflammatory drugs and anti-oxidants were negative in the inhibition of arachidonic acid-induced erythema. Cyproheptadine as an anti-histamine and -serotonin agent and morphine as a CNS acting agent were also negative. Erythema did not occur following treatment with linoleic acid, linolenic acid and gamma-linolenic acid. Bishomo-gamma-linolenic acid-induced erythema was inhibited by diclofenac sodium. The inhibition of acidic nonsteroidal anti-inflammatory drugs in this system seemed to be the result of a block of the enzymatic conversion of arachidonic acid to prostaglandins. The arachidonic acid-induced erythema in guinea pigs can serve as a new animal model for evaluating prostaglandins biosynthesis inhibitors such as anti-inflammatory drugs.