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| Fontana,M. D.; Lucas,H. S. M.; Vital Brazil,O.. |
| In 1919, Houssay and Negrete reported that venoms of Theraphosidae spiders induced neuromuscular blockade. In 1993, a purified toxin from Grammostola spider venom was found to block the P-type voltage-dependent calcium channel (VDCC), causing neuromuscular blockade. We studied the mode of action of Theraphosa blondii venom, a large Theraphosidae spider from Northern Brazil, Venezuela, and The Guyanas in mouse phrenic nerve-diaphragm preparation. This venom elicited a partially reversible neuromuscular blockade and did not depress directly evoked twitches or alter the membrane potential. Neostigmine produced only a poor antagonistic effect on partially blocked diaphragms. However, completely blocked miniature endplate potentials (m.e.p.ps) were reverted by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spider venom; Mouse diaphragm preparation; Neuromuscular junction; Theraphosa blondii. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-79302002000200010 |
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| Borja-Oliveira,C. R.; Kassab,B. H.; Soares,A. M.; Toyama,M. H.; Giglio,J. R.; Marangoni,S.; Re,L.; Rodrigues-Simioni,L.. |
| Two presynaptic phospholipases A2 (PLA2), neuwieditoxin-I (NeuTX-I) and neuwieditoxin-II (NeuTX-II), were isolated from the venom of Bothrops neuwiedi pauloensis (BNP). The venom was fractionated using molecular exclusion HPLC (Protein-Pak 300SW column), followed by reverse phase HPLC (µBondapak C18 column). Tricine-SDS-PAGE in the presence or absence of dithiothreitol showed that NeuTX-I and NeuTX-II had a molecular mass of approximately 14 kDa and 28kDa, respectively. At 10µg/ml, both toxins produced complete neuromuscular blockade in indirectly stimulated chick biventer cervicis isolated preparation without inhibiting the response to acetylcholine, but NeuTX-II reduced the response to KCl by 67.0±8.0% (n=3; p<0.05). NeuTX-I and NeuTX-II are probably... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chick biventer cervicis; Loose patch clamp; Nerve-muscle preparation; Neuromuscular junction; Neurotoxicity; PLA2 neurotoxin; Presynaptic action; Bothrops neuwiedi pauloensis; Neuwieditoxin-I; Neuwieditoxin-II. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992007000100008 |
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| Oshima-Franco,Y.; Leite,G. B.; Valério,A. A.; Hyslop,S.; Andriao-Escarso,S.; Giglio,J. R.; Prado-Franceschi,J.; Cruz-Höfling,M. A.; Rodrigues-Simioni,L.. |
| Bothrops jararacussu venom and its major toxin bothropstoxin-I (BthTX-I) possess myotoxic and neurotoxic properties. The efficacy of a rabbit antivenom raised against B. jararacussu venom in the neutralization of physiological, biochemical, and morphological changes induced by the venom and its major toxin BthTX-I was studied in mouse isolated phrenic nerve-diaphragm (PND) and extensor digitorum longus (EDL) preparations. The times required for 50% neuromuscular blockade in PND and EDL preparations for venom were 70+11.5 (S.E.M., n=5) min and 58+8 (n=16) (50 mu g/mL), and for BthTX-I 31+6 (n=3) min and 30+3 (n=5) min (20 mu g/mL), respectively. After 120 min incubation, creatine kinase (CK) concentrations in solution containing the EDL preparations were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bothrops venom; Myotoxin; Neutralization; Neuromuscular junction; Histological analysis; Bothrops jararacussu. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-79302002000200004 |
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