Estudo comparativo dos efeitos do veneno bruto de Brothrops neuwiedi goyazensis, B.n. paranaensis e B.n. diporus sobre a junção neuromuscular de preparações isoladas de ave e de mamifero

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Accidents caused by snakes in Brazil possesses importance of the medical point of view. In cases that the serpent was identified, 90,5% were caused by genera Bothrops, according to the Health Ministry of Brazil. The main causes of death are the acute renal insuficience, the shock, the acute breathing insuficienceand the septicemy. The Bothrops neuwiedi complex of snakes has a wide distribution in South America. In this work, we compared the pharmacological and phospholipase A2(PLA2) activities of venoms from three subspecies (B. n. goyazensis, B. n. paranaensis and B. n. diporus) of this complexoPLA2 activity was measured colorimetricalIy and pharmacological activity was assessed in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (pND) preparations. Comparison of the PLA2 activities of the venoms showed that the order of potency was B. n. diporus >B. n. paranaensis >B. n. goyazensis. In BC preparations, alI of the venoms (50, 100 and 200 ?g/ml, n=3-5 each) caused long-Iasting, concentrationdependent muscle contracture and twitch-tension blockade, and also inhibited the muscle. responses to ACh and KCI. The venoms were three times less potent in BC than in PND preparations. In avian preparations, B. n. goyazensis venom (50 ?g/ml) was only active at 37°C (50% blockade in 102:1:9min; meanj:SEM, n=5) whereas B. n. diporus venom (50 Ilg/ml) was active only at 22°C (50% blockade in 80:1:10min; meanj:SEM, n=5). In avian preparations, B. n. goyazensis (100 ?g /ml, at 37° or 22°C) and B. n. paranaensis (50 ?g/ml, at 22°C) venoms showed a small but significant increase in the twitch-tension (p<0.05) and only partial blockade (20-40% afier 120 min). These results indicate that these venoms contain compounds that interfere primarily with post-synaptic neurotransmission. In contrast to avian preparations, alI of the venoms (100 ?g/ml) caused total blockade of the twitch tension responses in PND within 45-100 min, at 37°C or 22°C, indicating that the neuromuscular blockade was not temperature-dependent in this preparation. In addition, the neuromuscular action ofthese venoms was not directly related to their enzymatic activity

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peçonhas diafragma

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