The neurotoxicity of the venom phospholipases A(2), notexin and taipoxin.
The presynaptically active, toxic phospholipases known as notexin and taipoxin are principal components of the venom of the Australian tiger snake and the Australian taipan respectively. The inoculation of the toxins into one hind limb of rats caused, within 1 h, the depletion of transmitter from the motor nerve terminals of the soleus muscle. This was followed by the degeneration of the motor nerve terminals and of the axonal cytoskeleton. By 24 h 70% of muscle fibers were completely denervated. Regeneration and functional reinnervation were almost fully restored by 5 days, but collateral innervation was common in the regenerated muscles, and this abnormality persisted for at least 9 months. The data provide an explanation for both the severity of neuromuscular paralysis that can accompany envenoming bites by tiger snakes and taipans and the difficulty experienced by physicians in managing the envenomed subjects.
Harris
J B
JB
School of Neurosciences, Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom.
Grubb
B D
BD
Maltin
C A
CA
Dixon
R
R
D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D004546:Elapid Venoms / Q000633:toxicity*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006614:Hindlimb; D009045:Motor Endplate / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D009046:Motor Neurons / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D009411:Nerve Endings / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D009466:Neuromuscular Blocking Agents / Q000633:toxicity; D009498:Neurotoxins / Q000633:toxicity*; D010243:Paralysis / Q000139:chemically induced / Q000503:physiopathology*; D010741:Phospholipases A / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D011950:Receptors, Cholinergic / Q000032:analysis; D012038:Regeneration / Q000187:drug effects
D004546:Elapid Venoms; D009466:Neuromuscular Blocking Agents; D009498:Neurotoxins; D011950:Receptors, Cholinergic; C005082:notexin; C015523:taipoxin; D010741:Phospholipases A; D000110:Acetylcholinesterase