Effect of Cerastes cerastes snake venom on the neuromuscular transmission of the chick biventer cervicis muscle preparation

Cerastes cerastes is an Egyptian viper from the family Viperidae and genus Cerastes. In general, snakes of the Elapidae family produce neurotoxic venoms targeting the nervous system, while snakes of the Viperidae family produce hemotoxic venoms targeting blood coagulation. Little is known about the neurotoxic action of cerastes venom. The present work was aimed to study the effect of C. cerastes crude venom on neuromuscular transmission, and to isolate and purify the fraction(s) responsible for that neurotoxicity. The venom was fractionated by gel filtration on sephadex G-50. The neurotoxicity was verified by neuromuscular technique (chick biventer cervicis muscle preparation, CBCM). Five different fractions (F1, F2, F3, F4, and F5) were collected by gel filtration. Both crude venom (40 µg/ml) and F1 (20 µg/ml) exhibited obvious neurotoxicity. They significantly reduced the twitch tension of (CBCM) and suppressed the contractile responses of CBCM to ACh (10^-3 M), carbachol (CCh, 2x10^-6 M), and KCl (60 mM). These results suggest that crude venom and F1 affect peripherally, and they are postsynaptically acting. Crude venom has phospholipase and proteinase activities, while the neurotoxic fraction (F1) has proteinase activity only.