Hypothermia induced in mice by injection of venom sac extract of hornets (Vespa orientalis, vespinae: hymenoptera)

Cardiovascular haemodynamics of oriental hornet venom sac extract

The effects of hornet venom sac extract on the functioning of the cardiovascular system was assessed in dogs by concomitant examination of the following parameters: Systemic blood pressure, blood pressure and the dp/dt derivative of the left ventricle of the heart, heart rate, direct measurement of the left ventricular wall thickness, cardiac output, and body temperature. The effect of adult hornet venom sac extract on the canine cardiovascular system was rapid and led to a sharp drop in the systemic blood pressure, a similar drop in the pressure and dp/dt derivative in the left ventricle, to bradycardia, immediate thickening of the left ventricular wall and to an immediate rise in the cardiac output. As for the canine temperature, this dropped immediately following the administration of venom sac extract and remained at the new low level for at least 30 min. The smaller molecular weight components (less than 10 kilodalton) in venom sac extract have been found to be responsible for the immediate effects of venom sac extract on the cardiovascular system. On the other hand the high-molecular weight components exert more delayed effects which lead to a cumulative disturbance of cardiac function.

Mastoparan induces hypothermia in mice

The polypeptide mastoparan, isolated from the venom of the Oriental Hornet, Vespa orientalis, induces hypothermia in white mice 15 minutes after its intraperitoneal injection. The hypothermic effect is induced by mastoparan obtained from different hornet and wasp venoms. The normal murine core temperature is lowered by mastoparan from 38 degrees C to as far as 33 degrees C. This lowering lasts for one hour and is reversible.

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.