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Inhibition of carrageenin‐induced rat paw oedema by crotapotin, a polypeptide complexed with phospholipase A 2
Author(s) -
Landucci Elen C.T.,
Antunes Edson,
Donato Jose L.,
Faro Renato,
Hyslop Stephen,
Marangoni Sérgio,
Oliveira Benedito,
Cirino Giuseppe,
Nucci Gilberto
Publication year - 1995
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1995.tb17178.x
Subject(s) - histamine , chemistry , phospholipase a2 , degranulation , bronchoconstriction , platelet , pharmacology , thromboxane b2 , platelet activating factor , arachidonic acid , thromboxane , bradykinin , thromboxane a2 , medicine , biochemistry , enzyme , receptor , asthma
1 The effect of purified crotapotin, a non‐toxic non‐enzymatic chaperon protein normally complexed to a phospholipase A 2 (PLA 2 ) in South America rattlesnake venom, was studied in the acute inflammatory response induced by carrageenin (1 mg/paw), compound 48/80 (3 μg/paw) and 5‐hydroxytryptamine (5‐HT) (3 μg/paw) in the rat hind‐paw. The effects of crotapotin on platelet aggregation, mast cell degranulation and eicosanoid release from guinea‐pig isolated lung were also investigated. 2 Subplantar co‐injection of crotapotin (1 and 10 μg/paw) with carrageenin or injection of crotapotin (10 μg/paw) into the contralateral paw significantly inhibited the carrageenin‐induced oedema. This inhibition was also observed when crotapotin (10–30 μg/paw) was administered either intraperitoneally or orally. Subplantar injection of heated crotapotin (15 min at 60°C) failed to inhibit carrageenin‐induced oedema. Subplantar injection of crotapotin (10 μg/paw) also significantly inhibited the rat paw oedema induced by compound 48/80, but it did not affect 5‐HT‐induced oedema. 3 In adrenalectomized animals, subplantar injection of crotapotin markedly inhibited the oedema induced by carrageenin. The inhibitory effect of crotapotin was also observed in rats depleted of histamine and 5‐HT stores. 4 Crotapotin (30 μg/paw) had no effect on either the histamine release induced by compound 48/80 in vitro or on the platelet aggregation induced by both arachidonic acid (1 m m ) and platelet activating factor (1 μ m ) in human platelet‐rich plasma. The platelet aggregation and thromboxane B 2 (TXB 2 ) release induced by thrombin (100 mu ml −1 ) in washed human platelets were also not affected by crotapotin. In addition, crotapotin (10 μg/paw) did not affect the release of 6‐oxo‐prostaglandin F 1α and TXB 2 induced by ovalbumin in sensitized guinea‐pig isolated lungs. 5 Our results indicate that the anti‐inflammatory activity of crotapotin is not due to endogenous corticosteroid release or inhibition of cyclo‐oxygenase activity. It is possible that crotapotin may interact with extracellular PLA 2 generated during the inflammatory process thereby reducing its hydrolytic activity.