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Flashcards in Muscle and nerve toxins Deck (14)
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What are potential sources of tetrodotoxin

Ingestion of animal containing tetrodotoxin - puffer fish
Bitten/stung by an animal with tetrodotoxin - blue ringed octupus


Is tetrodotoxin produced by the animals in which the sources arise

No, marine bacteria located in the animal produce it - symbiotic relationship - unclear as to how the animals show immunity to the toxin


What are some symptoms of tetrodotoxin

Numbness in lips and tongue, headache, vomiting, increased levels of paralysis, respiratory muscle paralysis leads to death (20mins-8hours)


What is the treatment for tetrodotoxin

Keep alive until tetrodotoxin is broken down by the body
Mechanically ventilate the patient to prevent death by respiratory paralysis - allows this time


What is the action of tetrodotoxin

Blocking of Nav channels
No action potential in motor/sensory neurons
Reduction in neurotransmitter release at the neuromuscular junction - No muscular action potential produced leading to paralysis


Which Nav channels are sensitive to tetrodotoxin

1.5,8,9 are insensitive channels


What are sources of dendrotoxins

Snake neurotoxins, mamba snake family


What are the symptoms of dendrotoxins

Early weakness/numbness at bite site
Ptosis - drooping eyelids, dysphagia (difficulty swallowing), Paresis (mild general paralysis around the body), Resp failure leads to death


What is the physiology of dendrotoxins

Blockage of Kv channels - depolarisation lasts longer so depletion of Ach stores at the presynapse
No more Ach to release results in no action potentials so no contraction


How do dendrotoxins affect K channels

Decrease K current to 25%


How are dendrotoxins treated

Antivenom, removes toxin from bound channels, prevents binding with channels


What are conotoxin sources

Cone snails


What is the target of conotoxins

Cav2.2 and Nav1.8 - block the channels in peripheral and CNS - may be beneficial for blocking pain signals


Conotoxin symptoms

Burning pain - paradoxically short term symptom due to nociceptor stimulation
Swelling at site
Numbness, CV and resp distress, loss of coordination, nausea, stomach cramp