Cholinergic and Anticholinergics

Question 1

M1 Receptors

Answer 1

Stomach Acid

CNS - Nausea, vomitting

Question 2

M2 Receptors

Answer 2

Heart

Question 3

M3 Receptors

Answer 3

Lung, Bronchoconstriction
Eyes, Near accommodation; Pupil constriction - Miosis, good for drainage
Bladder, Contract, and urination

SWEAT Gland (sympathetic!)

Secretions
- Mucous, Saliva, Tears

Question 4

Contra-I of Cholinergic Drugs

Answer 4

Asthma, Peptic Ulcers

Question 5

Pilocarpine

Answer 5

Non-selective Muscarinic Agonist, but used for M3 focus

• Treat Glaucoma and Dry mouth

SE: Asthma, COPD, Sweating, Blurred Vision

Question 6

Bethanechol

Answer 6

Non-selective Muscarinic Agonist

• Treat gastric atony (inability to contract)
• Treat urinary retention (safer than Pilocarpine due to lower M2 sensitivity - hence heart effects)

Question 7

Nicotine (low dose)

Answer 7

Nicotinic Agonist; for smoking cessation

Recall nicotinic receptors at autonomic ganglion hence indirect muscarinic cholinergic activity and adrenergic activity; + NMJ

• both Sympathetic and Parasymp activated
• NMJ activated too
• Muscle contraction
• Adrenal, CVS, GI, Carotid Bodies RR increase,
• Nausea vomiting
• Activating functions dominate

Question 8

Physostigmine
Donepezil
Neostigmine (myasthenia gravis)

Class and SE

Answer 8

(Reversible) AchE Inhibitors

SE: Abdominal Cramps, Hypotension, BC, Miosis

Question 9

Sarin effects and Pralidoxime

Answer 9

Sarin - organophosphate, suicide inhibitor of AchE

CNS: respi depression, coma, N&V
Autonomic muscarinic: BC, Blur vision, sweating, salivation, lacrimation
Somatic nicotinic: muscle twitching, flaccid paralysis (note diaphragm paralysis)

Pralidoxime: regenerates AcH

Question 10

Atropine treatment, side effects and contra-I

Note Benzatropine for Parkinson’s for M1 in CNS

Answer 10

Muscarinic Antagonist - Direct Muscarinic Blocker
- given for AchEI poisoning; Treatment of Bradycardia

Muscarinic Blocker;

SE (inhibited parasympathetic effects)

• Cutaneous vasodilation
• Heat, decreased sweating
• CNS delirium, confusion
• Blurred vision, increased IOP
• Dry mouth
• Urinary Retention
• Constipation

Contra-I for narrow angle glaucoma

Question 11

Nicotine (high dose)

Answer 11

Indirect Muscarinic (indirect) and Nicotinic BLOCKERS
Ganglionic Blocker (plus NM blocker function)

• Depolarising blockage
• Secondary non-depolarising blockage/ Densensitising blockage

SE: medullary depression, BC, NMJ blockage

Question 12

Neuromuscular Blocking Agents for surgical paralysis;

Answer 12

Indirect Anticholinergic Agent

1. Non-depolarizing (Pancuronium)
2. Depolarizing (Succinylcholine)

Phase I, depolarisation w muscle twiching
Phase II, desensitization w flaccid paralysis

Question 13

Botulinum Toxin

Answer 13

Indirect Anticholinergic Agent

Inhibit vesicular exocytosis of synaptic vesicles with Ach