ABSTRACT
The effect of Odonthobuthos doriae [O.d] scorpion venom at 0/3, 1 and 3, 10 microg/ml concentrations were investigated on nerve-muscle transmission, using the Twitch tension technique. A concentration of 0.3 microg/ml caused a small change in the twitch height in response to indirect muscle stimulation, but higher concentrations [1, 3, 10 microg/ml] caused a transient augmentation in twitch response followed by a large contracture in the chick biventer cervices [CBC] preparation. This effect could be defined as a complex action of the venom, predominately presynaptic, in which its' effects on postjunctional synapses is also maintained. In order to find out which bioactive fraction could explain the venom effects, the soluble crude venom was partially separated by the gel filtration method, using a Sephadex G50 column, and four fractions were separated. Two of the four purified fractions [O.d F[3], O.d F[4]] were characterized as toxic and their LD[50] values were lower than the crude venom. Unlike the O.d Fj and O.d F[2] fractions, O.d F[3] and O.d F[4] fractions caused a significant block in the twitch and contracture, in comparison to the control sample. in conclusion, fractions O.d F[3] and O.d F[4] are supposed to be as the biological active components of the O.d. venom