Central effects of Tityus serrulatus and Tityus bahiensis scorpion venoms after intraperitoneal injection in rats

Abstract

A great number of studies on scorpion venoms associate their effects to the autonomic nervous system, and few data are available about their action on the central nervous system (CNS). The aim of this work was to evaluate some central effects after intraperitoneal injection of Tityus serrulatus or T. bahiensis scorpion venoms. The hippocampal concentration of some neurotransmitters and their metabolites were determined. Electroencephalographic and behavioral observations were performed, and all brains were removed for histopathological analysis of hippocampal areas. Both venoms induced electrographic and behavioral alterations despite T. bahiensis venom affects less the electrographic activity than T. serrulatus venom. Neurochemical analysis demonstrated no alteration in the extracellular levels of almost all the neurotransmitters evaluated, at least in the hippocampus, and no neuronal loss in this area was observed. Meanwhile, extracellular concentration of HVA increased up to 10 times in approximately 1/3 of the animals of both groups. Scorpion venoms seem to exert a small but important central effect. More studies in this field are necessary because they may be useful in developing new strategies to reduce the damage caused by scorpion stings.

Effectiveness of the Androctonus Australis Hector Nanobody Nbf12-10 Antivenom to Neutralize Significantly the Toxic Effect and Tissue Damage Provoked by Fraction of Androctonus mauretanicus (Morocco) Scorpion Venom

“…Indeed, cerebral alterations were assumed to be the consequence of neurotransmitter releases [43][44][45][46][47][48][49][50][51]. More recently, similar structural damage in brain tissue (i.e., edema, hemorrhage, neuronal darkness) were evoked by a small scorpion toxin called Kaliotoxin isolated from Aah [52].…”

“…The LD 50 represents as amount of venom or toxic fraction leading to 50 % of mice surviving the injection [34,36]. Survivors were counted after 24h.…”

Comparative study between peripherally and centrally acting sublethal and lethal doses of Leiurus quinquestriatus scorpion venom in rabbits: The usefulness of the sodium channel blocker lidocaine

“…In animals, as was observed in this study, convulsion-related symptoms encompass wet dog shakes, staring, masticatory jaw movements, facial automatisms, orofacial movements, blinking, twitching and/ or shivering. Moreover, scorpion venom elicits autonomic overstimulation, manifesting as abdominal pain, vomiting, excessive sweating, salivation, diaphoresis, hyperglycemia, hyperamylasemia, cold extremities, hypo-/hyperpnea, pulmonary edema, tachy-/brady-arrhythmias, hyper-and/or hypotension (Ismail, 1995;Bosnak et al, 2009;Guidine et al, 2009;Nencioni et al, 2009). In this study, peripheral or central injection of LQQ venom into conscious rabbits (to avoid the masking effects of anaesthesia) lead to the characteristic systemic manifestations, in addition to symptoms of over-stimulation of autonomic nervous system and CNS excitation.…”

“…Despite the fact that neurological effects such as agitation, brain infarcts and convulsions, have been observed after scorpion envenoming (Mesquita et al, 2003;Bahloul et al, 2005;Boyer et al, 2009;Nencioni et al, 2009), action on the central nervous system (CNS) was originally excluded, since peptides do not cross the blood-brain barrier (Revelo et al, 1996). Neurological manifestations were explained at least in part, through the action of the venom toxins on the peripheral nervous system (Ismail, 1995).…”

“…However, Clot-Faybesse et al (2000) and Nunan et al (2003) reported finding scorpion toxins in the CNS after systemic injection in newborn mice, with a not fully developed blood-brain barrier. Moreover, following the peripheral inoculation of venom or toxins from the Tityus species, Nencioni et al (2009) postulated a central mechanism for systemic manifestations and Guidine et al (2009) suggested the involvement of the brainstem associated with cardiovascular control.…”