Cholinergic Agonists

Question 1

Direct-acting Agonist

Answer 1

Bind to and activate Muscarinic or nicotinic receptors

Question 2

Indirect-acting Agonist

Answer 2

Inhibit acetylcholinesterase

Question 3

Direct effect of Acetylcholine

Answer 3

Vasodilation(M3 effect)

Decrease in cardiac rate(M2 effect)

Decrease in rate of conduction in the S.A and AV node (M2 effect)

Decrease in the force of contraction

Question 4

What is the effect of Acetylcholine on Vasculature/endothelial cells?

Answer 4

Release of Nitric Oxide and vasodilation

Decrease in Blood pressure

Question 5

What is the effect of Acetylcholine on Eye Iris?

Answer 5

Miosis- Constriction

Question 6

What is the effect of Acetylcholine on Ciliary muscle?

Answer 6

accommodation of lens to near vision

Question 7

What is the effect of Acetylcholine on Salivary/sweat/lacrimal glands?

Answer 7

inc in secretions

Question 8

What is the effect of Acetylcholine on Bronchi?

Answer 8

constriction

Question 9

What is the effect of Acetylcholine on heart?

Answer 9

Dec. Heart rate Dec conductance velocity

Question 10

What is the effect of Acetylcholine on GI Tract?

Answer 10

Inc tonic and peristaltic activity

relaxation of sphincter

Question 11

What is the effect of Acetylcholine on Urinary bladder?

Answer 11

Contraction of detrusor muscle

relaxation of sphincter

Question 12

What are the two types of direct acting cholinergic Agonists?

Answer 12

Esters of choline and Alkaloids

Question 13

What are the Choline esters

Answer 13

Acetylcholine
methacholine
Bethanecol

Question 14

properties of Choline esters

Answer 14

Quaternary ammoniums

Poorly absorbed and distributed into the CNS

Acetylcholine is rapidly hydrolyzed

Methacholine and bethanecol more resistant to hydrolyzation

Question 15

uses of Acetylcholine

Answer 15

Obtain miosis after delivery of the lens in cataract surgery and other procedures where rapid miosis is required

Question 16

uses of Methacholine

Answer 16

Diagnosis of bronchial airway hyperactivity in subjects who do not have clinically apparent asthma

Question 17

uses of Bethanecol

Answer 17

postoperative urinary retention

atony(lack of physiological tone especially of a contractile organ.) of the urinary bladder

Question 18

What are the natural alkaloids

Answer 18

Pilocarpine and nicotine

Question 19

Pilocarpine

Answer 19

Partial muscarinic agonist

Tertiary amine

stable to hydrolysis by acetylcholinesterase

Question 20

uses of pilocarpine

Answer 20

Glaucoma

Treatment of dry mouth due to radio therapy for cancer of head and neck

Question 21

Adverse effects of muscarinic agonists

Answer 21

sweating
salivation
flushing
low blood pressure 
nausea
abdominal pain
diarrhea 
bronchospasm

Question 22

Nicotine

Answer 22

tertiary amine

agonist at nicotinic receptors

depending on the doses can either be stimulating or cause paralysis

Question 23

Nicotinic action at low doses

Answer 23

ganglionic stimulation via depolarization

Question 24

Nicotinic action at high doses

Answer 24

ganglionic blockade and neuromuscular blockade

Question 25

What are the anticholinesterases? indirect acting cholinergic agents

Answer 25

Edrophonium -binds reversibly to the active site carbamates- forms a covalent bond with the enzyme organophosphates- phosphorylate enzyme and covalent bond formed is very stable

Question 26

what is the mechanism of action for anticholinesterases?

Answer 26

inhibit cholinesterase. increase in the concentration of endogenous acetylcholine

Question 27

uses of Edrophonium

Answer 27

Diagnosis of myasthenia gravis reverse the neuromuscular block produced by non-depolarizing muscular blockers

Question 28

uses of Physostigmine

Answer 28

Treatment of overdoses of anticholinergic drugs

Question 29

uses of neostigmine

Answer 29

urinary retention cholinesterase inhibitor reversal of effects of nondepolarizing neuromuscular blockers after surgery Treatment of myasthenia gravis

Question 30

uses of pyridostigmine

Answer 30

treatment of myasthenia gravis Cholinesterase inhibitor

Question 31

Malathion

Answer 31

used in pesticides/insecticides

Question 32

Sarin

Answer 32

potent synthetic toxic agents biowarfare bombs

Question 33

Atropine

Answer 33

Reversible competitive antagonist at muscarinic receptors Tertiary amine: both central and peripheral muscarinic blocker

Question 34

Atropine action on : eye

Answer 34

Mydriases(dilation) and cycloplegia(focus on distant objects)

Question 35

Atropine action on : GI

Answer 35

reduces gastric motility

Question 36

Atropine action on : Urinary Tract

Answer 36

decreases hypermotility of urinary bladder (M3 Blockade)

Question 37

Atropine action on : CV system

Answer 37

Atrial M2 Blockade- moderate to high therapeutic doses cause tachycardia

Question 38

Atropine action on : Secretion

Answer 38

M3 blockade- Salivary, sweat, and lachrymal glands are blocked. inhibition of sweat glands can lead to high body temp

Question 39

Atropine uses

Answer 39

Antidote for cholinergic agonists block respiratory tract secretion prior to surgery

Question 40

Atropine adverse effects

Answer 40

Drymouth, blurred vision sandy eyes , tachycardia, constipation, urinary retention effect on CNS: restlessness, confusion, hallucinations, delirium

Question 41

Uses of Scopolamine

Answer 41

Prevention of motion sickness

Question 42

Ipratropium

Answer 42

used in the treatment of chronic obstructive pulmonary disease and asthma

Question 43

tropicamide

Answer 43

used as mydriatic for fundoscopy produces mydriasis with cycloplegia

Question 44

What is the contraindication of antimuscarinic agent?

Answer 44

If the patient has angle-closure glaucoma if the patient has prostatic hypertrophy and is elderly

Question 45

Ganglionic blocker

Answer 45

Remove the dominant control may occur by prolonged depolarization or antagonism of nicotinic receptors

Question 46

Uses of ganglion blocker

Answer 46

Hexamethonium was used for hypertension in the past Replaced because of their adverse effects

Question 47

Tubocurarine

Answer 47

nondepolarizing blocker competitive agonist use: as adjuvant drug in anesthesia during surgery to relax skeletal muscle

Question 48

Succinylcholine

Answer 48

Depolarizing blocker- done by binding to nicotinic receptor and depolarizing the junction. leads to flaccid paralysis Used in rapid endotracheal intubation

Question 49

botulinum toxin

Answer 49

injected locally into muscle for treatment of several diseases involving muscle spasm inhibitor of acetylcholine release