title: Hyperalgesic properties of 15-lipoxygenase products of arachidonic acid.
abstract: Induction of hyperalgesia by leukotriene B4 (LTB4), a potent chemotactic factor for polymorphonuclear leukocytes (PMNLs), depends on the generation by cutaneous PMNLs of mediators that are probably derived from the 15-lipoxygenation of arachidonic acid. The capacity of dihydroxyeicosatetraenoic acid (diHETE) products of the 15-lipoxygenation of arachidonic acid in PMNL to elicit hyperalgesia was evaluated by assessing the effects of intradermal injection of synthetic diHETEs on the pressure nociceptive threshold in rats. (8R,15S)-Dihydroxyeicosa-(5E-9,11,13Z)-tetraenoic acid [(8R,15S)-diHETE] produced a dose-dependent hyperalgesia, as measured by decrease in threshold for paw withdrawal. The isomer (8S,15S)-diHETE antagonized in a dose-dependent manner this hyperalgesia due to (8R,15S)-diHETE but did not suppress prostaglandin E2-induced hyperalgesia. (8S,15S)-DiHETE produced a dose-dependent hypoalgesia, as reflected by an increase in nociceptive threshold, suggesting a contribution of endogenous (8R,15S)-diHETE to normal nociceptive threshold. The hypoalgesic effect of (8S,15S)-diHETE was blocked by corticosteroids but not by the cyclooxygenase inhibitor indomethacin. Neither (8R,15S)-dihydroxyeicosa-(5,15E-9,11Z)-tetraenoic acid nor (8R,15S)-dihydroxyeicosa-(5,11E-9,13Z)-tetraenoic acid exhibited any hyperalgesic or hypoalgesic activity. The stereospecificity of the effect of (8R,15S)-diHETE suggests that the induction of hyperalgesia is a receptor-dependent phenomenon and that (8S,15S)-diHETE may be an effective receptor-directed antagonist. The (8R,15S)-diHETE and (8S,15S)-diHETE from PMNL, keratinocytes, and other epithelial cells may modulate normal primary afferent function and contribute to inflammatory hyperalgesia.
mesh_terms: D000818:Animals; D001091:Arachidonate Lipoxygenases; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors; D015232:Dinoprostone; D004305:Dose-Response Relationship, Drug; D007213:Indomethacin / Q000494:pharmacology; D007975:Leukotriene B4 / Q000031:analogs & derivatives* / Q000633:toxicity; D008084:Lipoxygenase / Q000378:metabolism*; D008297:Male; D009504:Neutrophils / Q000378:metabolism*; D010146:Pain / Q000139:chemically induced*; D011239:Prednisolone / Q000494:pharmacology; D011458:Prostaglandins E / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D001095:Arachidonic Acids; D016861:Cyclooxygenase Inhibitors; D011458:Prostaglandins E; D007975:Leukotriene B4; D016718:Arachidonic Acid; C030722:8,15-leukotriene B4; D011239:Prednisolone; D001091:Arachidonate Lipoxygenases; D008084:Lipoxygenase; D015232:Dinoprostone; D007213:Indomethacin