Effects of Brazilian scorpion venoms on the central nervous system

Abstract

In Brazil, the scorpion species responsible for most severe incidents belong to the Tityus genus and, among this group, T. serrulatus, T. bahiensis, T. stigmurus and T. obscurus are the most dangerous ones. Other species such as T. metuendus, T. silvestres, T. brazilae, T. confluens, T. costatus, T. fasciolatus and T. neglectus are also found in the country, but the incidence and severity of accidents caused by them are lower. The main effects caused by scorpion venoms – such as myocardial damage, cardiac arrhythmias, pulmonary edema and shock – are mainly due to the release of mediators from the autonomic nervous system. On the other hand, some evidence show the participation of the central nervous system and inflammatory response in the process. The participation of the central nervous system in envenoming has always been questioned. Some authors claim that the central effects would be a consequence of peripheral stimulation and would be the result, not the cause, of the envenoming process. Because, they say, at least in adult individuals, the venom would be unable to cross the blood-brain barrier. In contrast, there is some evidence showing the direct participation of the central nervous system in the envenoming process. This review summarizes the major findings on the effects of Brazilian scorpion venoms on the central nervous system, both clinically and experimentally. Most of the studies have been performed with T. serrulatus and T. bahiensis. Little information is available regarding the other Brazilian Tityus species.

Tb II-I, a Fraction Isolated from Tityus bahiensis Scorpion Venom, Alters Cytokines’: Level and Induces Seizures When Intrahippocampally Injected in Rats

“…It is known that convulsion often occurs in severe cases of scorpion envenomation [ 1 , 7 , 19 , 20 ], and its origin has been mainly related to systemic effects of the venom, altering the release of sympathetic and parasympathetic neurotransmitters [ 1 ]. It has also been demonstrated that central neurotransmitters, mainly glutamate, participate in this process (revised by [ 21 ]). However, the participation of cytokines has not been taken into account.…”

Scorpion venoms and associated toxins as anticancer agents: update on their application and mechanism of action

“…Nencioni, Neto, de Freitas, and Dorce (2018) summarized in detail the major findings on the impact of Brazilian scorpion venoms on the central nervous system (CNS). Most of the studies have been performed with Tityus spp.…”

Tb1, a Neurotoxin from Tityus bahiensis Scorpion Venom, Induces Epileptic Seizures by Increasing Glutamate Release

“…Tityus bahiensis is a Brazilian scorpion that is responsible for several accidents in the southeast region [16][17][18]. Their specific biological requirements, such as the habitat temperature and humidity variation, and their sexual reproduction restrict them to this geographic region [19].…”