Neurotoxic effects of three fractions isolated from Tityus serrulatus scorpion venom

Scorpion venoms contain low molecular weight basic polypeptides, neurotoxins, that are the principal toxicagents. These toxins act on ion channels, promoting a derangement that may result in an abnormal release of neurotransmitters.In the present study we investigated some of the effects of the F, H and J fractions isolated from Tityus serrulatusscorpion venom on the central nervous system of rodents. The venom was partially purified by gel filtration chromatography.The neurotoxic effect of these fractions was studied on convulsive activity after intravenous injection, and on electrographicactivity and neuronal integrity of rat hippocampus when injected directly into this brain area. The results showedthat intravenous injection of the F and H fractions induced convulsions, and intrahippocampal injection caused electrographicseizures in rats and neuronal damage in specific hippocampal areas. Fraction J injected intravenously reduced thegeneral activity of mice in the open field but induced no changes when injected into the brain. These results suggest thatscorpion toxins are able to act directly on the central nervous system promoting behavioural, electrographic and histologicalmodifications.

Behavioral, electroencephalographic, and histopathologic effects of a neuropeptide isolated from Tityus serrulatus scorpion venom in rats

The effects of intrahippocampal administration of a neuropeptide (TS-8F toxin) isolated from Tityus serrulatus scorpion venom have been determined on behavior, limbic seizures, and neuronal degeneration in rats. Behavioral observation showed orofacial automatism, wet dog shakes, and myoclonus. Concomitantly, the electroencephalographic record showed high-frequency and high-voltage spikes that evolved to seizure activity in the hippocampus and cortex. Seven days after TS-8F toxin microinjection, neuronal damage was observed in CA1 and CA2 pyramidal cells and in granular cells of the dentate gyrus. The results suggest that TS-8F toxin may be responsible, at least in part, by the epileptic effects observed with the crude venom. Thus, this toxin may be a useful tool in the study of some neurobiological process.

Brazilian scorpion venoms: pharmacological aspects

This review focuses on clinical, epidemiological and therapeutic aspects of envenomation caused by scorpions in Brazil. In addition, it presents studies with the crude venom and neurotoxins isolated from Tityus serrulatus scorpion venom. Such studies show the pharmacological effects of the venom and isolated toxins in experiments that use the scorpion venom and neurotoxins as neurobiological tools to study receptor sites in sodium channels and neurotransmitter release.