Tityus serrulatus is the most venomous scorpion in Brazil; however, it is not known whether its venom causes any harm to the offspring whose mothers have received it. This study investigates whether the venom of T. serrulatus may lead to deleterious effects in the offspring, when once administered to pregnant rats at a dose that causes moderate envenomation (3mg/kg). The venom effects were studied on the 5th and on the 10th gestation day (GD5 and GD10). The maternal reproductive parameters of the group that received the venom on GD5 showed no alteration. The group that received the venom on GD10 presented an increase in post-implantation losses. In this group, an increase in the liver weight was also observed and one-third of the fetuses presented incomplete ossification of skull bones. None of the groups that received the venom had any visceral malformation or delay in the fetal development of their offspring. The histopathological analysis revealed not only placentas and lungs but also hearts, livers and kidneys in perfect state. Even having caused little effect on the dams, the venom may act in a more incisive way on the offspring, whether by stress generation or by a direct action.

Scorpion venom neurotoxins are responsible for toxicity and pharmacological effects. They are active in sodium and potassium channels leading to an increase in the release of neurotransmitters, such as glutamate. Glutamate is found in large quantities in the hippocampus (HPC) and is involved in the long-term potentiation (LTP) induction. The HPC is known to be related to certain kinds of memory. The aim of this study is to evaluate the effects of Tityus serrulatus TS-8F toxin on rat behavior with emphasis on learning and memory. We analyzed the effects of different doses of TS-8F on rat behavior in home cages, open-field (habituation), inhibitory avoidance, T-maze, and hippocampus morphology. In the first two experiments, 0.05µg/animal dose of TS-8F did not cause convulsion but led to a decrease in locomotion (LO) frequency in the open-field first session. During the second session, rats receiving 0.03µg/animal TS-8F showed a decrease in LO and rearing frequency (RE); controls only showed decreased LO; and those receiving 0.05µg/animal showed no significant changes. In inhibitory avoidance, T-maze, and HPC morphology experiments no significant differences were observed. It is concluded that TS-8F may exert some influence in rat learning and memory and seems to be useful as a pharmacological tool. Further research is required to elucidate all possible uses of this toxin.

It has been previously shown that the crude venom of Tityus serrulatus can cause convulsions. This study was designed to investigate the neurotoxic effects of B, C, G, and K fractions isolated from this venom. Intravenous injection of these fractions in mice (0.6 - 6.0 mg/kg body weight) showed that the C fraction is a potent convulsant and G fraction decreased the threshold for tonic hand limb extension elicited by transauricular electroshock. Unilateral injection of B, C, and K fractions, but not G fraction, into the hippocampus of rats (0.6 - 6.0 µg) caused electroencephalographic alterations consisting of spikes and epileptic discharges that began in the hippocampus and evolved to the cortex. The following motor signs were observed: movements of facial muscles, wet dog shake, immobility, myoclonus, wild-running with clonus, and in some cases, loss of postural control. Intrahippocampal injection of B, C, and K fraction, but not G fraction, caused neuronal loss at the injection site as well as in other hippocampal areas. The effect of these fractions on epileptiform activity and on neuronal loss was dose-dependent. The severity of the epileptiform activity in the ipsilateral hippocampus correlated with the severity of the neuronal loss. The electrographic, behavioral, and histological changes induced by B, C, and K fractions were similar to those obtained with other drugs that are commonly used to induce convulsion. The convulsant effects of the crude venom may be caused by the fractions studied in this work.