Species differences in the neuromuscular activity of post-synaptic neurotoxins from two Australian black snakes (Pseudechis porphyriacus and Pseudechis colletti)

摘要: Abstract Bites by Australian black snakes (Pseudechis spp.) do not cause neurotoxicity in human envenoming. This is unusual as vitro has been reported for all Pseudechis spp. venoms. The present study aimed to identify, isolate and characterise neurotoxins from the venoms of porphyriacus colletti elucidate reason lack humans. α-Elapitoxin-Ppr1 α-elapitoxin-Pc1 were isolated P. colletti, respectively, using reverse-phase high performance liquid chromatography. Each toxin consisted 62 amino acids with molecular weights 6746.5 Da 6759.6 Da, respectively. caused concentration-dependent (0.1–0.3 μM) inhibition indirect twitches chick biventer cervicis nerve-muscle preparation. Both toxins inhibited contractile responses exogenous ACh CCh, but KCl, suggesting a post-synaptic mode action at nicotinic acetylcholine receptor (nAChR). CCh concentration–response curves obtained presence or absence α-elapitoxin-Ppr1 indicated pA2 values 6.97 ± 0.03 7.04 ± 0.07, Neither (0.1 μM) nor had significant effect on electrically-induced rat phrenic nerve-diaphragm When venom removed (10 μg/ml) was added both preparations, significantly less than that intact whole (10 μg/ml). current shows act pseudo-irreversible antagonists nAChR skeletal neuromuscular junction avian preparation more sensitive neurotoxic effects these mammalian