Poster 194.  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.553.

 

 

Effects Of Commercial Crotalic Antivenom And Rabbit Antiserum On The Neurotoxicity Of Crotalus durissus ruruima Venom And Its Crotoxin In Chick Biventer Cervicis Preparations. 

 

1Hernandez-Oliveira, S.S.; 1Oshima-Franco, Y.; 1Stellati-Pereira, R.; 1Barros, J.C.; 1Leite, G.B.; 1Panunto, P.C.; 2Borja-Oliveira, C.R.; 3Marangoni, S.; 1Hyslop, S.; 1Rodrigues-Simioni, L.

 

1 Depto Farmacologia - FCM/UNICAMP; 2 Laboratório Nacional de Luz Sincrotron (LNLS) - Campinas/SP e 3 Depto Bioquímica - IB/UNICAMP.

 

Crotalusdurissus ruruima is a rattlesnake subspecies found principally in the Brazilian Amazon. In this work, we evaluated the ability of commercial crotalic antivenom (CAV, raised against C. d. terrificus venom) and rabbit antisera (RAS) raised against C. d. ruruima venom and its crotoxin to protect against the neurotoxicity of this venom and its crotoxin in chick isolated biventer cervicis preparations. The preparations were mounted in aerated (95% O2/5% CO2) Krebs solution at 37°C for indirect stimulation. CrTX was isolated from C. d. ruruima venom by chromatography on Sephadex G-75 and HPLC. The time (in min; mean+S.E.M.; n=6-8) required for 50% and 90% blockade was, respectively, 43±4 and 57±5 for the venom (5 mg/ml), and 20.4±3 and 42±2.4 for crotoxin (5 mg/ml). Venom and crotoxin increased the contractures to exogenous ACh (110 mM) by 17.4+7.4% and 25.2+14%, respectively, but had no significant effect on contractures to KCl (20 mM). The preincubation of venom with CAV or either of the RAS  in a 1:1 (10 mg/ml) ratio for 30 min at 37ºC (n=5-7) showed that CAV and RAS offered >90% protection against the neuromuscular blockade induced by C. d. ruruima venom and crotoxin and also prevented the changes in the contractures to exogenous ACh and KCl. These results show that C. d. ruruima venom and its crotoxin have a presynaptic action similar to that previously described for C. d. terrificus venom and its crotoxin, and that CAV and RAS effectively neutralized the neuromuscular blockade induced by the former venom and its crotoxin.

 

Support: CNPq and FAEP/UNICAMP

 

Correspondence to: saher@unicamp.br