Fractionation of scorpion (Mesobuthus tamulus) venom and the impact of specific fractions on glutamate metabolism.

The fractionation of the venom of Indian red scorpion (Mesobuthus tamulus) was performed using CM-52 (carboxy methyl cellulose) ion-exchange chromatography. The toxic potential of these fractions were tested on lepidoptera larvae and mice. The CM-52 fractions, which showed toxicity were further used to study their impact on glutamate metabolism. The glutamate content increased and glutamine synthetase and glutamate decarboxylase activity levels were elevated in envenomated animals. The present results reveal that glutamine is rapidly metabolized to glutamate and gamma-aminiobutyric acid indicating that the pool of neurotransmitters is maintained and regulated by glutamine biosynthesis. The scorpion neurotoxins inhibit the glutamate dehydrogenase activity, suggesting a decreased deamination of glutamate.