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Type: Artigo de periódico
Title: Functional Characterization Of A Basic D49 Phospholipase A2 (lmtx-i) From The Venom Of The Snake Lachesis Muta Muta (bushmaster).
Author: Damico, Daniela C S
Bueno, Lilian G F
Rodrigues-Simioni, Léa
Marangoni, Sérgio
da Cruz-Höfling, Maria Alice
Novello, José Camillo
Abstract: The whole venom of Lachesis muta muta is preponderantly neurotoxic but moderately myotoxic on the chick biventer cervicis preparation (BCp). We have now examined these toxic activities of a basic phospholipase A(2), LmTX-I, isolated from the whole venom. LmTX-I caused a significant concentration-dependent neuromuscular blockade in the BCp. The time to produce 50% neuromuscular blockade was 14.7+/-0.75 min (30 microg/ml), 23.6+/-0.9 min (10 microg/ml), 34+/-1.7 min (2.5 microg/ml) and 39.2+/-3.6 min (1 microg/ml), (n=5/concentration; p<0.05). Complete blockade with all tested concentrations was not accompanied by inhibition of the response to ACh. At the highest concentration, LmTX-I (30 microg/ml) significantly reduced contractures elicited by exogenous KCl (20mM), increased the release of creatine kinase (1542.5+/-183.9 IU/L vs 442.7+/-39.8 IU/L for controls after 120 min, p<0.05), and induced the appearance of degenerating muscle fibers ( approximately 15%). Quantification of myonecrosis indicated 14.8+/-0.8 and 2.0+/-0.4%, with 30 and 10 microg/mlvenom concentration, respectively, against 1.07+/-0.4% for control preparations. The findings indicate that the basic PLA(2) present on venom from L. m. muta (LmTX-I) possesses a dominant neurotoxic action on isolated chick nerve-muscle preparations, whereas myotoxicity was mainly observed at the highest concentration used (30 microg/ml). These effects of LmTX-I closely reproduce the effects of the whole venom of L. m. muta in chick neuromuscular preparations.
Subject: Acetylcholine
Crotalid Venoms
Muscle Contraction
Muscle, Skeletal
Neuromuscular Blocking Agents
Phospholipases A
Phospholipases A2
Potassium Chloride
Citation: Toxicon : Official Journal Of The International Society On Toxinology. v. 47, n. 7, p. 759-65, 2006-Jun.
Rights: fechado
Identifier DOI: 10.1016/j.toxicon.2006.02.007
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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