Drugs And The Parasympathetic Nervous System

Question 1

In the parasympathetic nervous system, acetylcholine

Answer 1

Is released from postganglionic nerve endings where it activates muscarinic acetylcholine receptors on the effector tissues, named after the selective agonist actions of muscarine

Question 2

M1 receptors

Answer 2

Found on neurons in CNS -> slow excitatory postsynaptic potential in ganglia

Question 3

M2 receptors

Answer 3

Regulate heart rate and force of contraction

Question 4

M3 receptors

Answer 4

Responsible for glandular secretion, contraction of visceral smooth muscle and vascular relaxation

Question 5

Muscarinic receptors activate phospholipase C

Answer 5

Which leads to production of IP3 and DAG. IP3 releases Ca2+ from the sarcoplamic reticulum which reacts with DAG to form protein kinase C to contract smooth muscle

Muscarinic receptor 1,3 and 5

Question 6

Muscarinic receptors inhibit adenylate Cyclades

Answer 6

Which causes a decreases of the levels of cAMP

Muscarinic receptors 2 and 4

Question 7

Muscarinic 2 receptors can

Answer 7

Activate potassium channels and inhibit calcium channels

Question 8

Direct acting cholinomimetic drugs

Answer 8

Have mainly muscarinic effects at end effectors

Question 9

Indirect acting cholinomimetic drugs e.g. acetylcholinesterase inhibitors

Answer 9

Potential transmission at all cholinergic junctions therefore have muscarinic, ganglionic and skeletal muscle effects

Question 10

Therapeutic uses for cholinomimetic

Answer 10

Intestinal and urinary bladder atony (contraction)
Glaucoma -> build of aqueous humour in front of the eye
Alzheimer’s

Question 11

Therapeutic uses of anti muscarinic

Answer 11

Pre-anaesthetic medication
Opthamological uses
Gastrointestinal antispasmodic agents
Treatment of poisoning by cholinomimetics