|
Poster 19. 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.378. |
Myotoxics and preliminary studies electrophysiological of Alternatustoxin (BtTX), a PLA2 Lys49 from Bothrops alternatus (Urutu) snake venom.
1Ponce-Soto, L.A., 2 de Santis, L.H., 1Fagundes F.H.R., 1Bonfim, V.L., 1Damico, D.C.S., 1Ribeiro, D.A., 3Barros, J.C., 3Rodrigues-Simioni, L. and 1Marangoni. S.
1 Departament of Biochemistry, 2 Departament of histology and embryology, Institute of Biology and 3 Departament of Pharmacology Faculty Medical Science UNICAMP – Brazil.
After the total neuromuscular blockade or after 120 min incomplete neuromuscular blockade by fraction neurotoxic Bothropsalternatustoxin (BtTX) PLA2 Lys49 (control preparations were incubated inTyrode solution for 120 min, n=5), the chiken biventer cervicis muscle preparations were fixed in Bouin solution for 24-48 h followed by dehydration and embedding in parafin. Sections 5 mm thick were stained with hematoxylin-eosin (H.E.) prior to examination by light microscopy and the hypercontraction of the truncated extremities of the fibers besides the evidenced alterations was showed. We can notice that the fibers are hyalines, with amorphous aspect, without apparent scratches, more these are going appearing hypercontraction of the extremities of the fibers and in the measure that the determinations increases. Beyond the alterations of the volume along the same fiber portions appear where the fibers seem to be destroyed and the hypercontraction of the areas of destructions of the fibers increase, evidencing a larger lesion of the same ones. They are known as “delta lesions”, and it was proposed that they correspond to areas of degeneration beneath portions of ruptured plasma membrane. The new factor neurotoxic was tested at five concentrations (0.5, 1, 2, 5, 10 and 20 mg/ml) produced 50% neuromuscular blockade in 65.51 ± 7, 40.44 ± 4, 35.27 ± 3, 24.24 ± 1, 22.23 ± and 21.23 ± 3 min, respectively (mean ± SEM, n=5 each). The effects electrophysiological was also examined and measure and revealed that this fraction neurotoxic in the concentration of 1 mg/ml, were not go able to take too much depolarization state in the region of the badge motorboat similar to outside of the same one, in the carbacol presence in the concentration of 12 mg/ml like control in the depolarization. These results reveal that this fraction could have an action of presynaptic type in the junction neuromuscular which not taking to a membrane depolarization in the region of the plate outside of the same one.
Correspondence to: pelao01@hotmail.com