Neuromuscular blocking action of the Theraphosa blondii spider venom
J. venom. anim. toxins
;
8(2): 316-323, 2002. ilus, graf
Artigo
em Inglês
| LILACS
| ID: lil-314699
RESUMO
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 neostigmine. These results can be explained by the presence of toxins in the venom that interact with the endplate receptor at the acetylcholine sites (curareminetic toxins) and toxins that inhibit the P-type voltage-dependent calcium channel (VDCC) (ômega-toxins). This study shows that Theraphosidae venoms, especially those of the Theraphosa blondii, are a source of curaremimetic toxins and ômega-toxins of possible interest as tools in bioscientific research.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Venenos de Aranha
/
Bloqueadores Neuromusculares
Limite:
Animais
Idioma:
Inglês
Revista:
J. venom. anim. toxins
Assunto da revista:
Toxicologia
Ano de publicação:
2002
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Butantan Institute/BR
/
UNICAMP/BR
/
UNICAMP. School of Medical Sciences/BR
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