Histamine, 5-HT & hyaluronidase in the venom of the scorpion Lychas laevifrons (Pock).

Factors involved in the pathophysiological changes such as severe pain, burning sensation, redness, swelling and edema in case of the scorpion L. laevifrons were investigated. The presence of pain-producing autacoids histamine 2.1 +/- 0.18 micrograms/mg and 5-HT 0.23 +/- 0.1 micrograms/ml was confirmed by thin layer chromatography and bioassay. Histamine releasing substance was detected in vitro in the chopped guineapig lung. Venom also contained hyaluronidase 5 x 10(-4) N-acetyl-D-glucosamine released/h/mg, which facilitates spread of the toxic principles in the tissues. It is concluded that histamine, 5-HT, histamine-releasing factor and hyaluronidase are partly involved in the pathophysiological changes induced by the venom. It is suggested that mepyramine and cyproheptadine may prove useful in the management of scorpion envenomation.