Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/100439
Type: Artigo de periódico
Title: An Unusual Presynaptic Action Of Bothrops Insularis Snake Venom Mediated By Phospholipase A2 Fraction
Author: Cogo J.C.
Prado-Franceschi J.
Giglio J.R.
Corrado A.P.
Cruz-Hofling M.A.
Donato J.L.
Leite G.B.
Rodrigues-Simioni L.
Abstract: A phospholipase A2-contraining fraction was isolated from the venom of Bothrops insularis by a combination of gel filtration on Sephadex G-150 and ion exchange chromatography on DEAE-Sephadex. Peak IV of the latter chromatography containing all of the phospholipase A2 (PLA2) activity, was assayed on isolated neuromuscular preparations. In the mouse phrenic nerve- diaphragm incubated in Tyrode at 37°C, the PLA2 fraction produced an initial increase in the twitch tension and in the frequency of the mepps, followed by a dose-dependent, irreversible blockade. The replacement of 1.8 mM Ca2+ by 4 mM Sr2+ inhibited the neuromuscular blocking effect of the fraction. In the chick biventer cervicis preparation incubated with Krebs solution at 37°C, the PLA2 fraction induced blockade but did not affect the response to acetylcholine and K+, excluding the involvement of post-synaptic and direct muscular effects. A low temperature (18-22°C) incubation prevented the neuromuscular effect from developing. These results suggest that the PLA2-containing fraction acts predominantly at presynaptic sites at the neuromuscular junction. This fraction also accounts for most Of the pharmacological effects of the crude venom.
Editor: 
Rights: fechado
Identifier DOI: 10.1016/S0041-0101(97)00174-8
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0031859758&partnerID=40&md5=60268f94887e47b8fc46891558861504
Date Issue: 1998
Appears in Collections:Unicamp - Artigos e Outros Documentos

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