INTRASPECIFIC VARIATION IN NEUROTOXIC AND MYOTOXIC ACTIVITIES OF Bothrops neuwiedii VENOMS

C. R. BORJA-OLIVEIRA(1), A. M. SOARES(2,3), S. R. ZAMUNÉR(1), S. HYSLOP(1), J. R. GIGLIO(3), J. PRADO-FRANCESCHI(1), L. RODRIGUES-SIMIONI(1)

(1)Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brasil; (2)Departamento de Biotecnologia, Universidade de Ribeirão Preto, (UNAERP), Ribeirão Preto, SP, Brasil; (3)Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brasil.

ABSTRACT: Snake venoms frequently vary in composition. In this work, we compared the neurotoxic and myotoxic activities of 16 lots of Bothrops neuwiedii venoms from different regions of Brazil, using chick biventer cervicis preparations. The neuromuscular blockade varied from 2% to 100% after 120 min incubation with venoms (50 mg/ml). In all cases, this blockade was irreversible and concentration-dependent; at low concentrations (10-20 mg/ml), 15 of the 16 venom lots failed to abolish responses to acetylcholine (110 mM), but blocked responses to KCl (13.4 mM), and induced contracture. At 5-20 mg/ml, the most active venom totally blocked twitch-tension without affecting responses to acetylcholine and KCl. Polyacrylamide gel electrophoresis for basic proteins showed that the most active samples contained a band that was absent in the less active venoms. These results indicate that there may be considerable intraspecific variation in the neurotoxic activity of B. neuwiedii venoms, whereas myotoxic activity is less variable

KEY WORDS: Bothrops neuwiedii venom, intraspecific variation, myotoxicity, neurotoxicity, neuromuscular blockade.

CORRESPONDENCE TO:

L. Rodrigues-Simioni - Departamento de Farmacologia da Faculdade de Ciências Médicas da Universidade Estadual de Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Caixa Postal 6111, 13083-970, Campinas, SP, Brasil. Phone: 55 19 3788-7482; Fax: 55 19 3289-2968  Email simioni@obelix.unicamp.br