Many neurotoxic polypeptides (NPs) from venom of the scorpion Leiurus quinquestriatus (LqV) have been isolated and functionally characterized that were found to block voltage-activated ion channels in excitable tissues in both mammals and insects. This study aims to reveal the time-dependent alternations of these electrolytes in plasma that induced by (LqV) in vivo.
Rabbits were injected subcutaneously with a sub-lethal dose of approximately 0.12 mg/km body weight of crude (LqV). Photometric techniques have been used to monitor changes in the concentrations of Na⁺, K⁺, and Ca⁺⁺ in plasma six times; the first sample considered as control, the other five samples were collected in 36 minutes interval (after LqV injection). Correlation and regression analysis have shown that potassium and Calcium concentration tended to decrease (r=-0.706) and (r=-0.586) respectively whereas, concentration of Sodium tended to increase (r=0.635). Percentage of concentration change from control showed highly significant fluctuation during the first two hours, sodium was highly decreased by -72.29% below control 36 minutes after injection, for potassium and calcium, concentrations were increased; after 72 minutes potassium raised by 173.76% above control, calcium highest reading observed after 36 minutes (44.03% above control). 108 minutes after injection, percentage of change from control for all the ions was very close to each other (30.54%, 26.31% & 31.67% above control for sodium, potassium and calcium respectively). 144 and 180 minutes after injection, less fluctuation was observed.
Neurotoxic venom of this scorpion was found to change serum concentration of three fundamental electrolytes in nervous system biochemical mechanism. In addition this change may greatly affect toxin binding to ion channels as well as homeostatic balance. We suggest that, fatal symptoms due to scorpion stings are not only limited to direct interactions of PNs with VGSCs, but also toxin-affected neuro-chemical homeostasis could affect the behaviour of VGSCs.