Poster 196 - Comparison of the pharmacological and phospholipase activities of venoms from three

Poster 196. 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.555.

Comparison Of The Pharmacological And Phospholipase Activities Of Venoms From Three Subspecies (Bothrops neuwiedi diporus, B. n. goyazensis and B. n. paranaensis) of the Bothrops neuwiedi complex

¹Abreu, V.A.; ¹Dal Belo, C.; ¹Hernandes-Oliveira, S.S.; ²Borja-Oliveira, C.R.; ¹Hyslop, S.; ³Furtado, M.F.D. & ¹Rodrigues-Simioni, L.

1 Departamento de Farmacologia, FCM-UNICAMP, Campinas, SP; 2 Laboratório Nacional de Luz Sincrotron, Campinas, SP; 3 Laboratório de Herpetologia, Instituto Butantan, São Paulo, SP, Brazil.

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 complex. PLA2 activity was measured colorimetrically 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, all of the venoms (50, 100 and 200 mg/ml, n=3-5 each) caused long-lasting, concentration-dependent 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 mg/ml) was only active at 37ºC (50% blockade in 102±9 min; mean+SEM, n=5) whereas B. n. diporus venom (50 mg/ml) was active only at 22ºC (50% blockade in 80±10 min; mean+SEM, n=5). In avian preparations, B. n. goyazensis (100 mg/ml, at 37° or 22ºC) and B. n. paranaensis (50 mg/ml, at 22ºC) venoms showed a small but significant increase in the twitch-tension (p<0.05) and only partial blockade (20-40% after 120 min). These results indicate that these venoms contain compounds that interfere primarily with post-synaptic neurotransmission. In contrast to avian preparations, all of the venoms (100 mg/ml) caused total blockade of the twitch tension responses in PND within 45-100 min, at 37ºC or 22ºC, indicating that the neuromuscular blockade was not temperature-dependent in this preparation. In addition, the neuromuscular action of these venoms was not directly related to their enzymatic activity.