Exam 3: Cholinergic Neurotransmission and Cholinomimetics Flashcards
What are the sites the of drug actions for cholinergic neurotransmission?
- Synthesis
- Storage
- Release
- Receptort binding
- Degradation
- Reuptake/ recycling
How does hemicholinium interfere with cholingeric site of action?
Blocks the reuptake of choline by CHT
How does Vesamicol interfere with cholingeric site of action?
Inhibits ACh reuptake into a synaptic vesicles
How does Botulinum toxin interfere with cholingeric site of action?
Inhibits Snaps from releasing synaptic vesicle containing the ACh
How does black widow venom toxin interfere with cholingeric site of action?
Increases the release of ACh into the neuromuscular junction
How does neostigime interfere with cholingeric site of action?
Inhibits ACh breakdown from cholinergic receptor
Where are M1 receptors found?
Nerves, CNS, ganglia, gastric parietal cells
What is the G protein associated with M1?
Gq
What secondary messengers are stimulated by Gq M1 receptors?
Increased IP3, depolarization from decreased K+ current
Where are M2 receptors the found?
Heart, nerves, smooth muscle
What secondary messengers are stimulated by Gi?
- Decrease in cAMP
- Increase K+ currents
- Decrease in Ca++ current
What is the G protein associated with M2?
Gi
Where are M3 receptors found?
Exocrine glands, smooth muscle, endothelium
What secondary messengers are stimulated by Gq M3 receptors?
Increased IP3
Increased Ca++ current
What G protein is associated with M4?
Gi
What G protein is associated with M5?
Gq
Describe the structure of a nicotinic receptor?
- 5 separate proteins subunits
- Cation selective the channels (Na+ and Ca2+)
- 2 ACh binding sites on alpha subunits
What protein subunits are found of muscle nicotinic receptors?
a1, b1, δ, y (e for y in fetus)
What protein subunits are found of neuronal nicotinic receptors?
a and b subunits (mostly a3/b4 and a4/b2)
Compare the response rates of nicotinic and muscarinic stimulation by ACh?
N: Fast (milliseconds)
M: Slow (seconds)
What are the types of ACh receptors?
Muscarinic and Nicotinic
What are the types of the muscarinic receptors?
M1-5
Various target tissues
What are the types of nicotinic receptors?
Muscle and neuronal
What receptors are associated with skeletal muscles?
Muscle nicotinic receptor