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|Type:||Artigo de periódico|
|Title:||INHIBITION OF CARRAGEENAN-INDUCED RAT PAW EDEMA BY CROTAPOTIN, A POLYPEPTIDE COMPLEXED WITH PHOSPHOLIPASE A(2)|
|Abstract:||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 mu g/paw) and 5-hydroxytryptamine (5-HT) (3 mu g/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 mu g/paw) with carrageenin or injection of crotapotin (10 mu g/paw) into the contralateral paw significantly inhibited the carrageenin-induced oedema. This inhibition was also observed when crotapotin (10-30 mu g/paw) was administered either intraperitoneally or orally. Subplantar injection of heated crotapotin (15 min at 60 degrees C) failed to inhibit carrageenin-induced oedema. Subplantar injection of crotapotin (10 mu g/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 mu g/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 mM) and platelet activating factor (1 mu 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 mu g/paw) did not affect the release of 6-oxo-prostaglandin F1 alpha 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.|
PHOSPHOLIPASE A(2) ACUTE INFLAMMATION
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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