Please use this identifier to cite or link to this item:
|Type:||Artigo de periódico|
|Title:||Mn2+ Ions Reduce The Enzymatic And Pharmacological Activities Of Bothropstoxin-i, A Myotoxic Lys49 Phospholipase A2 Homologue From Bothrops Jararacussu Snake Venom|
|Abstract:||Bothropstoxin-I (BthTX-I), a myotoxic Lys49 phospholipase A2 (PLA2) homologue isolated from Bothrops jararacussu snake venom, causes a range of biological effects, including myonecrosis, mouse paw edema, irreversible neuromuscular blockade and lysis of cell cultures. Among eight divalent cations assayed, Mn2+ was the most effective in reducing mouse paw edema induced by BthTX-I (25μg). Preincubating BthTX-I with Mn2+ (1.0mM) reduced mouse paw edema by 70% and myotoxicity by 60% in mice injected i.m. with 50μg toxin. Mn2+ (50μl of a 1mM solution) administered within 1min at the site of toxin injection was still but less effective in antagonising BthTX-I-induced myotoxicity. Mn2+ (1.0mM) completely prevented BthTX-I (1.4μM)-induced neuromuscular blockade in the mouse phrenic-nerve diaphragm preparation. Mn2+ (0.25mM) protected about 85% of NB41A3 cells from lysis when coincubated with BthTX-I (1.0μM) for 25h. Preincubation with 0.25mM Mn2+ increased the sensitivity of the cells to subsequent lysis by BthTX-I in the absence of Mn2+. BthTX-I (1μM) caused extensive fatty acid release (from 0.8% of the total radiolabeled lipid in control cells to 56% with toxin) when incubated with the NB41A3 cell line for 25h. PLA2 activity observed in cell cultures after addition of BthTX-I was considerably reduced by 0.25mM Mn2+. Mn2+ ions constitute a promising agent to assess the action mechanism and the effects of enzymatic inhibition on the pharmacological activity of Lys49 PLA2 homologues. © 2002 Elsevier Science Ltd. All rights reserved.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.