kaolinite and phenylbenzoquinone

The effects of alminoprofen and other non-steroidal antiinflammatory drugs (NSAIDs) on the writhing reaction caused by kaolin, acetylcholine, phenylquinone and zymosan were studied. Aspirin, indomethacin, ibuprofen and diclofenac-Na, as cyclooxygenase inhibitors, showed similar potency ratios on four writhing tests, although, alminoprofen exhibited a somewhat rather higher potency ratio on kaolin- and zymosan-induced writhing models than on acetylcholine- and phenylquinone-induced writhing models. All NSAIDs, cyclooxygenase inhibitors except alminoprofen showed similar shapes in illustrations of potency ratio when the potency of aspirin was expressed as 1.0. The potency of alminoprofen produced a figure unlike those of other cyclooxygenase inhibitors. These results suggest that alminoprofen has a different pharmacological profile from other general NSAIDs in terms of analgesic action. This combination method with potency ratios for writhing reactions caused by the above four inducers could be a simple method for classification of pharmacological profiles of the analgesic actions of NSAIDs.

Topics: Acetylcholine; Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzoquinones; Kaolin; Male; Mice; Mice, Inbred ICR; Pain; Pain Measurement; Propionates; Quinones; Zymosan

Kaolin induced a clear and reproducible writhing reaction when intraperitoneally injected into mice. A simultaneous injection (i.p.) of soybean trypsin inhibitor (SBTI) significantly suppressed the kaolin-induced writhing reaction. This writhing reaction was markedly potentiated by a simultaneous injection (i.p.) of captopril. In an in vitro experiment kaolin caused kinin-release in mouse plasma, possibly through the activation of prekallikrein. This activation of plasma prekallikrein and kinin-release were inhibited in the presence of SBTI. Some non-steroidal anti-inflammatory agents inhibited the kaolin-induced writhing reaction dose-dependently. These results suggest that kaolin-induced writhing reaction may be caused by the released bradykinin through activation of the plasma kallikrein-kinin system. This model is a novel and simple tool for assessment of analgesic agents.

Topics: Acetylcholine; Analgesics; Animals; Behavior, Animal; Benzoquinones; Bradykinin; Disease Models, Animal; Kaolin; Male; Mice; Mice, Inbred ICR; Pain; Quinones