B.5 - Poisoning of the CNS (mechanism of action, effects, symptoms)

Question 1

Which poisons affect the CNS?

Answer 1

• Tropane Alkaloids
• Isoquinoline Alkaloids
• Piperidine Alkaloids
• Diterpenoid CNS Poisons
• Triterpenoid CNS Poisons
• Thiaminase Enzyme

Question 2

How do Tropane Alkaloids Affect the CNS?

Answer 2

1. Act as antagonists of acetylcholine
2. Act on smooth and cardiac muscle
3. Promote sympathetic predominance

Question 3

What are the symptoms of Tropane Alkaloids?

Answer 3

• Dry mouth
• Tachycardia
• Tachypnea

Question 4

How do Isoquinoline alkaloids/opioids affect the body?

Answer 4

1. Bind to opiod neuronal receptors
2. Close Ca²⁺ channels, open K⁺
3. Supresses pain signals

Question 5

What are the symptoms of Isoquinoline alkaloids/opioids?

Answer 5

• Pinpoint pupils
• Vomiting
• Paralysis
• Urinary Retention

Question 6

How do piperidine alkaloids affect the body?

Answer 6

1. Nicotinic cholinergic receptors blocked in PNS

Question 7

What are the symptoms of piperidine alkaloids?

Answer 7

• Paralysis
• Bradypnea
• Bradycardia
• Respiratory Paralysis

Question 8

How do Diterpenoid CNS poisons affect the body?

Answer 8

1. Opens permanently the voltage-gated Na⁺ channels
2. Inhibits Na⁺/Ca²⁺ echangers, stops repolarisation

Question 9

What are the symptoms of Diterpenoid CNS poisons?

Answer 9

• Paralysis
• Vomiting
• Asphyxia
• Cardiac Arrest

Question 10

How do Triterpenoid CNS poisons affect the body?

Answer 10

1. Inhibition of Acetylcholinesterase
2. Na⁺ channels stay open
3. Action potentials and muscle contractions halt

Question 11

What are the symptoms of Triterpenoid CNS poisons?

Answer 11

• Respiratory Depression
• Paralysis
• Vomiting
• Diarrhoea

Question 12

How do Thiaminase enzymes affect the body?

What are the Symptoms?

Answer 12

1. Releases thiamine
2. Causes low levels of Acetyl-CoA
3. Metabolic coma, Death