DGN - Nicotinic Receptors Flashcards
1
Q
What are properties of the M1 receptor?
A
Type:
- Neural
Location:
- CNS
Function:
- Gastric acid secretion
- Gut motility
2
Q
What are properties of the M2 receptor?
A
Type:
- Cardiac
Location:
- Atria and presynaptic terminals
Function:
- Cardiac inhibition
- Neural inhibition
3
Q
What are properties of the M3 receptor?
A
Type:
- Glandular
Location:
- Exocrine glands, smooth muscle and vascular endothelium
Function:
- Secretion
- Smooth muscle contraction
- Vasodilation
4
Q
What are Nicotinic Receptors, and what is their common feature?
A
Nicotinic Receptors are ligand-gated ion channels that are permeable to cations
- They are not G-coupled receptors.
5
Q
What are the 2 types of Nicotinic receptors?
A
N1 - Neuromuscular Junction
N2 - Autonomic ganglia, CNS and adrenal medulla
6
Q
Name some agonists of Nicotinic receptors (3)
A
- Acetylcholine
- Nicotine- stimulates autonomic ganglia
- Dimethylphenylpiperazinium (DMPP)- stimulates autonomic ganglia
7
Q
What is the selective antagonist for Nicotinic receptors?
A
Hexamethonium
- Shown in the cat nictitating membrane preparation (Paton and Zaimis, 1949)
8
Q
What are the main 2 properties of Hexamethonium
A
- Blocks the nicotinic receptor- no agonist action
- Reduces blood pressure (beneficial in hypertension)
9
Q
What are some side effects of Hexamethonium? (7)
A
- Dry mouth
- Reduced gastric acid secretion
- Constipation
- Urinary retention
- Blurred vision
- Postural hypotension
- Sexual dysfunction
10
Q
Hexamethonium vs Decamethonium
A
Hexamethonium (6 carbons)
- More effective at ganglionic block
- Higher affinity for N2 nicotinic receptors
Decamethonium (10 carbons)
- More effective at neuromuscular block
- Higher affinity for N1 nicotinic receptors
