Cortical cerebral blood flow is enhanced by hornet venom.

This study examined the effect of Oriental hornet venom sac extract (VSE) on the rate of local blood flow in the cerebral cortex of rats. Sublethal doses of VSE in isotonic saline solution were injected into the femoral vein of anaesthetised rats and the rate of blood flow was assessed by the hydrogen clearance technique both before the envenomation as well as during the following 150 min. The injection of VSE was found to induce a prolonged elevation of blood flow in the cerebral cortex. The time of occurrence of this elevation varied in different rats and so also the intensity of the elevation, ranging between 47-212% of the basal values. No exceptional or toxic phenomena were recorded in the course of this investigation. It would seem that the factor(s) responsible for boosting the blood flow is probably one or more of the water soluble components of the hornet venom.