TsIV

The TsIV toxin, isolated from T. serrulatus venom, does not discriminate between tissue-specific sodium channel subtypes and has been found to affect sodium channels from rat ventricular myocytes, rat cortical neurons and mouse skeletal muscle cells.^[5] Clinical manifestations of T. serrulatus envenoming include local pain at the site of the sting and systemic manifestations such as vomiting, profuse sweating, psychomotor agitation or restlessness, sinus tachycardia or bradycardia, arterial hypertension or hypotension, cardiac arrhythmias other than sinus tachycardia or bradycardia, cardiac failure, shock, tachypnea, pulmonary oedema and laboratory abnormalities such as leukocytosis, hyperglycaemia and increased amylase enzyme activity.^[6][7][8] Martin et al. recorded the toxicity of TsIV as LD₅₀ after subcutaneous (s.c.) and intracerebroventricular (i.c.v.) injection. The LD₅₀ of TsIV per 20 g mouse was 0.4 μg for s.c. injection and 24 ng for i.c.v. injection.^[2]

In clinical practice, Tityus poisoning is treated by intravenous administration of heterologous antivenoms. These antivenoms are obtained by the immunisation of horses with a mix of venoms derived from T.Serrulatus and T.Bahiensis.^[9] Several preclinical studies have identified epitopes that are present in many different toxins from the T. serrulatus scorpion. This could lead to the development of an antidote that reacts with the same epitope located on these different toxins.^[10] Additionally, studies examined reactivity between horse anti-Ts antisera and synthetically produced peptides that corresponded to the amino acid sequence of several Ts toxins, including TsIV. The aim of these studies was to ascertain the neutralizing potential of these antivenoms by examining their reactivity with different epitopes of T.serrulatus toxins.^[11]