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Authors
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A.C.Mancin,
A.M.Soares,
S.H.Andrião-Escarso,
V.M.Faça,
L.J.Greene,
S.Zuccolotto,
I.R.Pelá,
J.R.Giglio.
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Crotamine, a 4.88 kDa neurotoxic protein, has been purified to apparent
homogeneity from Crotalus durissus venom by gel filtration on Sephadex G-75.
When injected (i.p. or s.c.) in adult male Swiss mice (20-25 g), it induced a
time-dose dependent analgesic effect which was inhibited by naloxone, thus
suggesting an opioid action mechanism. When compared with morphine (4 mg/kg),
crotamine, even in extremely low doses (133.4 microg/kg, i.p., about 0.4% of a
LD50 is approximately 30-fold more potent than morphine (w/w) as an analgesic.
On a molar basis it is more than 500-fold more potent than morphine. It is also
much more potent than the lower molecular weight crude fractions of the same
venom. The antinociceptive effects of crotamine and morphine were assayed by the
hot plate test and by the acetic acid-induced writhing method. Therefore, both
central and peripheral mechanisms should be involved. Histopathological analysis
of the brain, liver, skeletal muscles, stomach, lungs, spleen, heart, kidneys
and small intestine of the crotamine injected mice did not show any visible
lesion in any of these organs by light microscopy. Since crotamine accounted for
22% (w/w) of the desiccated venom, it was identified as its major
antinociceptive low molecular weight peptide component.
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