Macrophage activation, phagocytosis and intracellular calcium oscillations induced by scorpion toxins from Tityus serrulatus

The research described here is focused upon studying the activation of mice peritoneal macrophages when submitted to in vitro effects of Tityus serrulatus scorpion venom and its major toxic peptides. Several functional events were analysed, such as: cytotoxicity, spreading, extent of phagocytosis, vacuole formation and changes of internal calcium concentration. Among the main results observed, when macrophages are subjected to the effects of soluble venom of Tityus serrulatus scorpion venom, a partially purified fraction (FII) or a pure toxin (Ts1), are an increment in the percentage of phagocytosis and vacuole formation, a decrement of the spreading ability, accompanied by oscillations of internal calcium concentration. The net results demonstrate that scorpion venom or its major toxins are effective stimulators of macrophage activity; the effect of whole soluble venom or partially purified fractions is due to the toxic peptides, seen here clearly with Ts1. The possible involvement of Na+-channels in these events is discussed. A basic understanding of the underlying molecular mechanisms responsible for macrophage activation should serve as a foundation for novel drug development aimed at modulating macrophage activity.