Evoked potential changes in cats following injection of an extract from the venom sac of the oriental hornet (Vespa orientalis).

Venom sac extract from the hornet Vespa orientalis was injected (via the subclavian artery) into cats and its effects on evoked potentials in two different sensory pathways (auditory and somatosensory) was investigated. A comparison was made between the venom sac extract from adult hornets and that from young (0-24 hr of age) hornets. There was a bimodal change in blood pressure, a hypothermic effect and a decrease in amplitude of the last waves of the auditory and somato sensory pathways when venom sac extract of adult hornets was injected. Venom sac extract from young hornet workers had the same influence on the blood pressure, did not affect thermoregulation and the effect on the auditory and somato sensory pathways were less consistent. Adult venom sac extract had mainly a central effect whilst the venom sac extract from young hornets (in larger doses) affected the central and/or peripheral nervous system. The central effects could be interpreted as due to opening of the blood-brain barrier by the venom.