Muscle toxins

Question 1

What are symptoms of Tetrodoxin if ingested?

Answer 1

Numbness of lips and tongue, facial parasthesia, headache, nausea, dizziness, diarrhoea, vomiting, increasing paralysis, respiratory paralysis leading to death

Question 2

What can block ACh release?

Answer 2

Tetanus toxin, botulinum toxin

Question 3

What can block AChR?

Answer 3

Bungarotoxin, tubocurarine

Question 4

What is the effect of Nav block?

Answer 4

Failure of neurotransmission, reduction neurotransmitter release at NMJ, loss sensation first as sensory nerves are outside bundles then muscle paralysis

Question 5

What Nav’s are sensitive to TTX?

Answer 5

Nav1-7 except 1.5

Question 6

What Nav’s are not sensitive to TTX?

Answer 6

Nav1.8-9 and 1.5

Question 7

What do TTX study on snakes show?

Answer 7

Size of current smaller with TTX

Question 8

Where is variable sensitivity to TTX shown in humans?

Answer 8

Brain and muscle Nav 374 a tyrosine and is sensitive but heart Nav 374 is a cysteine which is insensitive

Question 9

What sort of neurotoxin is dendrotoxin?

Answer 9

Snake neurotoxin of the mamba family

Question 10

What are symptoms of dendrotoxin poisoning?

Answer 10

Early weakness/ numbnesss at bitten extremity, systemic response to 30 minutes to 1 hour after initial bite, ptosis, ophthalmoplegia, dysphagia, paresis, respiratory failure

Question 11

What is the site of action of dendrotoxin?

Answer 11

Kv channels on neurons and muscles

Question 12

What are the pain targets for contoxins?

Answer 12

Cav2.2 and Nav1.8 in nociceptive nerve endings, Cav2.2, Cav3.2 and Nav- on central targets in spinal cord

Question 13

What are symptoms of Conotoxin poisoning?

Answer 13

Burning pain, swelling, numbness, cardiac and respiratory depression, muscle weakness, loss of coordination, ptosis, headache, nausea, stomach cramps, lips become stiff, blurred vision, paralysis, coma