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|Type:||Artigo de periódico|
|Title:||Neutralization Of The Pharmacological Effects Of Bothropstoxin-i From Bothrops Jararacussu (jararacuçu) Venom By Crotoxin Antiserum And Heparin|
Da Cruz-Hofling M.A.
|Abstract:||Bothropstoxin-I (BthTX-I), the principal myotoxin of Bothrops jararacussu venom, is devoid of phospholipase A 2 (PLA 2) activity but capable of blocking neuromuscular transmission in mouse nerve-muscle preparations. In this study, the ability of crotoxin antiserum and heparin in preventing the neurotoxic and myotoxic effects of BthTX-I was investigated. Phrenic nerve-diaphragm preparations (PND) stimulated indirectly with supramaximal stimuli (0.2 ms, 0.1 Hz) were incubated with BthTX-I (20 μg/ml) alone or with BthTX-I preincubated with antiserum or heparin for 30 min at 37°C prior to testing. Control preparations were incubated with Tyrode solution, antiserum or heparin alone. BthTX-I (20 μg/ml) produced 50% neuromuscular blockade in the PND preparations in 31 ± 4 min, with complete blockade occurring in 120 min. The antiserum and heparin significantly prevented the neuromuscular blockade caused by BthTX-I (84 ± 4% and 100% protection, respectively). Light microscopy examination of the muscles at the end of the 120 min incubation showed that BthTX-I damaged 48 ± 6% of the fibers. Preincubating the toxin with antivenom significantly reduced the extent of this damage (only 15 ± 4% of fibers affected, corresponding to 69% protection, P < 0.01) whereas heparin offered no protection (34 ± 7% of fibers affected, not significantly different from that seen with toxin alone). These results show that the antivenom was more effective in neutralizing the myotoxic effects of BthTX-I than was heparin. © 2001 Elsevier Science Ltd. All rights reserved.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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