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Poster 15. Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil. Abstracts... J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.374. |
Comparative study of neurotoxicactivity from Lachesis muta mutavenom in mouse and chick nerve-muscle preparations.
1Damico, D.C.S.,2Rodrigues-Siomini, L., 1Ponce-Soto, L.A.,1Fagundes F.H.R., 1Bonfim, V.L., 1Marangoni, S. and 1Novello, J.C.
1 Departament of Biochemistry, institute of Biology and 2 Departament of Pharmacology, Faculty of Medical Science, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
The effects of Lachesis muta muta venom were examined in vitro using the mouse phrenic nerve diaphragm and chick biventer cervicis muscle preparations (n=5) ± MSE p<0.05. Indirectly stimulated on mouse phrenic nerve-diaphragm muscle preparations suspended in Tyrode solution were incubated with venoms for up to 120 min and Krebs solution for chick biventer cervicis. At 10 mg/ml (blockage 50%), mouse phrenic nerve diaphragm doesn’t take to blockade and chick biventer cervicis was 30.4 ± 2.0 min. At 20 mg/ml (blockage 50%) mouse phrenic nerve diaphragm was 107 ± 9.3 min. and chick biventer cervicis was 31.2 ± 1.9 min. and 50 mg/ml was 71 ± 8.2 min and 28 ± 2 min for mouse phrenic nerve diaphragm and for chick biventer cervicis respectively. The addition of Ach (60 and 120 mM) or KCl (13.4 mM) before and after the addition of the venom from Lachesismuta muta in preparation chick biventer cervicis stimulated indirectly caused contracture. The whole venom was able to reduce the contract induced by the Ach 60 mM (50 mg/ml) 32.3 ± 1.4% and Ach 120 mM 28.3 ± 2.1%. The dose 20 mg/ml was (Ach 60 mM) 100 ± 7.0% and Ach 120 mM was 80 ± 5.0%. The dose 10 mg/ml was (Ach 60 mM) 85 ± 6.0% and Ach 120 mM 72 ± 6.2% respectively. The reduction of the response to KCl (13.4 mM) of 50, 20 and 10 mg/ml doses; was 40 ± 3%; 60 ± 4% and 61 ± 5% respectively. These results support the evidence that in the venom of Lachesismuta muta, one or several factors neurotoxics still unknown are able to take to the blockade of the contractile response in the junction neuromuscular. The answer difference in both preparations nerve muscle evidences the sensibility of the preparation chick biventer cervicis for the venom of Lachesismuta muta. The decrease of the response contracturants to the Ach and KCl suggests the presence of factors miotoxics, which can be also related with the neurotoxicity, fact that needs to be studied better.
Correspondence to: dcdamico@unicamp.br