Toxinological profile of the Bidder’s organ extract of the toad Bufo melanostictus (Schneider)

The present investigation explored the possible toxinological effects of the Bidder's organ extract (BO-extract) of the toad Bufo melanostictus (Schneider) on experimental animals. The LD50 of the BO-extract was found to be 12.5 mg/kg (i.v) in male albino mice. BO-extract, produced significant fall of body temperature in male normothermic albino mice but not in hyperthermic male albino rats. Pentobarbitone-induced sleeping time was significantly potentiated in mice. Bo-extract produced hypertensive action on cat and rat blood pressure which was totally antagonised by a-adrenergic blocker. On isolated heart, BO-extract initially in-creased the rate of contraction and finally produced irreversible cardiac arrest. On isolated guinea pig auricle, it also produced irreversible blockade of contraction. BO-extract significantly increased cutaneous capillary permeability in guinea pig and produced vasoconstrictor effect on rat hind-quarter perfusion. It produced quick contractile response on isolated guinea pig ileum, an action antagonised by cyproheptadine. At lower dose BO-extract potentiated the electrical stimulation induced twitch response on isolated rat phrenic nerve diaphragm and chick biventer cervicis and at higher doses it produced irreversible blockade of chick biventer cervicis muscle. BO-extract did not possess haemorrhagic activity but possessed strong haemolytic activity on washed goat RBC (HD50= 150 'g).