EFFECT OF DENERVATION ON THE MYOTOXICITY OF Bothrops jararacussu VENOM ON THE FAST- AND SLOW-TWITCH MUSCLES IN MICE

TOMAZ, M.A.; CALIL-ELIAS, S.; FERNANDES, F.F.A.; MORAES, R.A.M.; DRUSANO, M.F.; MELO, P.A.

Departamento de Farmacologia Básica e Clínica, Instituto de Ciências Biomédicas, CCS, Cidade Universitária – UFRJ, 21941-560, Rio de Janeiro, Brasil.

We examined the effect of denervation, by the sectioning of the sciatic nerve, on myotoxic effect of B. jararacussu venom on isolated EDL (Extensor digitorum longus – a fast- twitch muscle) and SOL (Soleus – a slow – twitch muscle) from mouse, as well as their total content of the enzyme creatinekinase (CK). Myotoxicity was assessed in vitro by loss of CK from muscles continuously perfused with physiological saline solution (PSS) alone or  with crude B. jararacussu venom (25mcg/ml). The increase of rate of CK released (above basal level) induced by venom was measured. EDL and SOL had the same range of basal rate of CK release (0.25-0.36 ±0.04 U.g^-1.h^-1 (N =12), weight (7-12 mg) . The  rate of CK release after 60 minutes of exposure to the venom, from EDL control, 7, 14 and 21 days after denervation were 13.67 ± 2.5,  9.55 ± 2.1,  5.10 ±1.4 and  3.12 ± 0.7 U.g^-1.h^-1 (N =4-6),  respectively. While on SOL muscle  were  and 3.02 ± 0.9,  2.28 ±0.3, 0.13 ± 0.02 and 0.05 ± 0.05 U.g^-1.h^-1 (N =4-6 ), respectively. The  CK content decreased circa of  40% (EDL) and 60% (SOL)   on the day 7 and decreased of 48% and 60% on day 14, for EDL and SOL respectively. These data show that EDL is more sensitive to B. jararacussu venom than is SOL, despite the difference in total CK content.

Financial support: CNPq-PIBIC, FAPERJ, FUJB-UFRJ, CAPES, FOGART-MIRT .

CORRESPONDENCE TO:

CALIL-ELIAS, S., Departamento de Farmacologia Básica e Clínica, Instituto de Ciências Biomédicas, CCS, Cidade Universitária – UFRJ, 21941-560, Rio de Janeiro, Brazil. Email: sabrinac@antares.com.br