Muscarinic And Nicotinic Blockers

Question 1

Functions of nervous system

Answer 1

1) sensation
2) integration
3) response

Question 2

What does somatic and ANS innervate

Answer 2

Somatic nervous system innervates skeletal muscles
ANS innervates Cardiac, smooth muscles and glandular epithelium

Question 3

ACH is a neurotransmitter in

Answer 3

All motor fibers leaving CNS
Autonomic ganglia
Postganglionic parasympathetic fibers
Postganglionic sympathetic fibers in M, sweat glands
Adrenal medulla
Motor neurons running to striated muscles

Question 4

Examples of Nicotinic receptor agonists

Answer 4

Nicotine, acetylcholine, choline, epibartidine, lobeline, varenicline and cytisine

Question 5

Dominant receptor in ganglion is _______
List other receptors that can be found

Answer 5

Nicotinic NN receptors are the dominant
Others: M1,M2, adrenergic, dopaminergic, aminergic, peptidergic receptors

Question 6

Selective Nicotinic agonist (Natural)

Answer 6

Nicotine( small doses)
Lobeline

Question 7

Selective Nicotinic agonist (Synthetic)

Answer 7

DMPP Dimethyl phenyl piperazinium
TMA tetramethyl ammonium

Question 8

Non selective muscarinic agonists

Answer 8

Acetylcholine, pilocarpine, Carbachol, anti cholinesterase

Question 9

Excessive amounts of selective Nicotinic agonists leads to

Answer 9

Sustained depolarization and ganglion block

Question 10

Clinical use of nicotine

Answer 10

Nicotine can be used as transdermal patches to treat nicotine dependence and can also aid smoking cessation

Question 11

Clinical use of varenicline

Answer 11

As a partial agonist it can reduce both the craving and pleasurable effect of cigarettes and other tobacco products
Through this mechanism it helps some patients quit smoking

Question 12

Cholinergic blocking drugs

Answer 12

Muscarinic antagonists, parasympatholytics, anticholinergics

Question 13

Muscarinic receptor sites

Answer 13

Heart
Smooth muscles of GIT
Salivary glands
Genitourinary tract
Urinary bladder

Question 14

List the cholinergic antagonists

Answer 14

Vesamicol
Hemicholinium
Botulinum toxins
Non depolarizing blocking agent e.g tubocurarine
Depolarizing blocking agents e.g suxamethonium

Question 15

What does vesamicol inhibit

Answer 15

It inhibits VAT vesicular acetycholine transporter so acetylcholine won’t be transported into vescicles for storage

Question 16

What does Hemicholinium inhibit

Answer 16

Inhibits choline transporter so choline can’t enter the neuron

Question 17

Botulinum what does it do

Answer 17

It cleaves snare proteins and without snare proteins vescicles cannot fuse with membrane and then released

Question 18

Example of non depolarizing blocking agent and function

Answer 18

Tubocurarine
Prevents acetylcholine from binding to post synaptic receptor

Question 19

Example of depolarizing blocking agents and function

Answer 19

Suxamethonium
Blocks action of acetylcholine on post synaptic cleft and causes continuous depolarization until there is sensitivity of receptor

Question 20

Where is M1 located

Answer 20

Primarily CNS ( cortex, hippocampus, corpus striatum), stomach

Question 21

Function of M1 receptors on CNS

Answer 21

Improves learning , memory and motor function

Question 22

Clinically selective anti cholinergic drugs on M1 receptors

Answer 22

Pirenzepine, telenzepine, dicyclomine, trihexyphenidyl

Question 23

Clinical effects of M1 receptors

Answer 23

Hydrogen ion secretion

Question 24

Clinical correlates of m2 receptors on CNS

Answer 24

Tremor, analgesia

Question 25

Function of M2 receptors at presynaptic terminals/ cholinergic nerve endings of peripheral and central neurons

Answer 25

Reduces acetylcholine release

Question 26

Clinically selective anti cholinergic drugs on M2 receptors

Answer 26

Tripitamine, methoctramine

Question 27

Effect of M3 on vascular smooth muscle

Answer 27

It’s activity is mediated through the release of NO to produce vasodilation

Question 28

Clinically selective M3 anticholinergics

Answer 28

Darifenacin, solifenacin, oxybutynin, tolterodine

Question 29

Antagonist of M4 receptor

Answer 29

Himbacine

Question 30

Function of M4 receptors

Answer 30

They function as inhibitory auto receptors for acetylcholine When activated m4 receptors inhibit ACH release in striatum

Question 31

List the anti muscarinic drugs Natural

Answer 31

Atropine (DL hyoscyamine) Scopolamine ( L hyoscine)

Question 32

List the anti muscarinic drugs Synthetic tertiary structural analogue of atropine

Answer 32

Homatropine

Question 33

List the anti muscarinic drugs Synthetic quaternary structural analogue of atropine

Answer 33

1) Atropine methyl nitrate 2) homatropine methyl bromide 3) methscopolamine bromide 4) Ipratropium 5) Tiotropium

Question 34

List the anti muscarinic drugs Synthetic tertiary structurally non related to atropine

Answer 34

Pirenzepine Dicyclomine Cyclopentolate Oxyphenycyclimine Tropicamide

Question 35

List the anti muscarinic drugs Synthetic quaternary structurally non related to atropine

Answer 35

Methantheline Propantheline Isopropamide Glycopyrrolate

Question 36

Natural alkaloids from antimuscarinic drugs

Answer 36

Atropine Hyoscine (scopolamine)

Question 37

Myadriatics semi synthetic derivatives

Answer 37

Homatropine

Question 38

Antiasthmatics semi synthetic derivatives

Answer 38

Ipratropium Tiotropium bromide

Question 39

GI spasmolytics semi synthetic derivatives

Answer 39

Hyoscine butyl bromide

Question 40

Myadriatics synthetic compounds

Answer 40

Tropicamide, cyclopentolate

Question 41

Myadriatics synthetic compounds

Answer 41

Tropicamide, cyclopentolate

Question 42

Myadriatics synthetic compounds

Answer 42

Tropicamide, cyclopentolate

Question 43

Myadriatics synthetic compounds

Answer 43

Tropicamide, cyclopentolate

Question 44

In the CNS atropine produces mainly _______ effects , low doses cause _________ higher doses cause __________ and ___________

Answer 44

Excitatory effects mild restlessness Agitation and disorientation

Question 45

The central effects of atropine on CNS could be opposed by

Answer 45

Anticholinesterases e.g phsyostigmine (an effective antidote to atropine poisoning)

Question 46

Hyoscine in low dose causes ______

Answer 46

Marked sedation similar to atropine at high doses

Question 47

Atropine like drugs affect _______ reducing ________ and _________ in _______ disease

Answer 47

Extrapyramidal system Involuntary movements and Rigidity In parkinston’s disease

Question 48

Atropine produces a mild anaesthetic action on the _____

Answer 48

Cornea

Question 49

How is atropine eliminated

Answer 49

50% metabolized in the liver and the remaining excreted unchanged in urine

Question 50

Half life of atropine

Answer 50

Approx 4 hrs

Question 51

Anti cholinergic toxicity mnemonics

Answer 51

Hot as a hare ( hyperthermia) Dry as a bone (dry skin) Red as a beet (flushed) Blind as a bat (mydriasis) Mad as a hatter (delirium)

Question 52

Anticholinergic toxicity

Answer 52

1) altered level of consciousness (hallucinations, delirium, coma, slurred speech) 2) seizures 3) sinus tarchychardia 4) hypertension 5) Mydriasis 6) Dry eyes 7) Dry mouth 8) reduced bowel sounds 9) constipation 10) urinary retention 11) hyperthermia

Question 53

Management of toxicity

Answer 53

1) control hyperthermia using cold sponging or ice bags 2) agitation might require physical constraints or chemical constraints ( benzodiazepines) 3) if ingested gastric labake 4) Antidote: physiostigmine 1-3 mg SC or IV for both central and pheripheral effects Neostigmine ineffective for central effects

Question 54

Management of anticholinergic toxicity is contraindicated in patients with

Answer 54

Bradychardia, intraventricular conduction delay, AV nodal block ,asthma,seizures and wheezing

Question 55

Atropine delays gastric ________ and delays __________ of other drugs

Answer 55

Emptying Absorption

Question 56

Antacids interfere with absorption of _________

Answer 56

Anticholinergics