BIOCHEMICAL PHARMACOLOGICAL AND MORPHOLOGICAL STUDIES OF THE VENOM FROM THE CHINESE SCORPION BUTHUS MARTENSI KARSCH

Abstract

The present study provides biochemical separation of the crude venom of the Chinese scorpion Buthus martensi Karsch (MKV), as well as pharmacological evidence and morphological changes produced by the crude venom and some toxins purified from MKV. This study was carried out therefore to determine the possible mechanism(s) that could account for or contribute to the effects of the venom and purified toxin on adrenergic and nitrergic transmissions. The effects of Buthus martensii Karsch venom (MKV) on adrenergic responses were investigated using the rat isolated anococcygeus muscle (Acm), since several scorpion venoms can cause peripheral sympathetic nerve stimulation with enhanced adrenergic responses. The effects of phentolamine (5然), guanethidine (5然), tetrodotoxin(2然), desipramine (1.5然) and reserpine pretreatment in viva (5 mg/kg s.c. x 24 hr and 5 mg/kg i. p. x 3 hr) on contractile responses of the rat Acm to field stimulation, noradrenaline (3然), tyramine (10然), crude MKV (2痢/ml), carbachol (3然) and potassium chloride (50mM) were compared. Phentolamine, guanethidine, tetrodotoxin and reserpine pretreatment completely blocked the contractile responses of the Acm to MKV and to field stimulation, but desipramine potentiated the responses. The responses to NA were completely blocked by phentolamine, but were potentiated by guanethidine, desipramine and reserpine pretreatment. The contractile responses to tyramine were completely blocked by phentolamine, desipramine as well as reserpine pretreatment. The low doses (0.1痢/ml x 3) of MKV which did not produce any observable increase in tone of the anococcygeus muscle, potentiated the contractile responses to field stimulation, but not the responses to exogenous NA. Thus, the adrenergic agonist action of MKV in the rat isolated anococcygeus muscle is mediated by some prejunctional mechanism(s) of action, presumably stimulating the release of neurotransmitter noradrenaline.