Cholinoceptor Activating & Cholinesterase inhibiting Drugs

Question 1

what are the 2 main cholinergic receptors?

Answer 1

Nicotinic (Nm, Nn) and muscarinic (M1, M2, M3)

Question 2

fill in the red spaces or say where do we find these receptors?

Answer 2

Question 3

Fill in the red spaces or mention what effect will the receptor have in the target organ

Answer 3

Also remember that M2 will have decreased AV conduction

Question 4

Acetylcholine or drugs acting like acetylcholine produces following effects in body:

• Heart
• blood vessels
• smooth muscle of lungs
• smooth muscle of ballder
• spincters of the GI and bladder
• pupils
• glands

Answer 4

1. Heart : Reduces HR (Bradycardia),FOC, CO and BP
2. Blood vessel: Vasodilatation and lowers BP
3. Smooth muscle contraction in GIT, bronchus, and bladder: Thus there will be Diarrhea, Bronchoconstriction and Urination
4. Sphincters in GIT and bladder: Relaxation
5. Pupil: Miosis and ciliary muscle contraction
6. Glands : more Salivation, sweating, gastric acid secretion , tracheobronchial secretion, lacrimation and urination

Question 5

ACh carrying nerves are called as what?

Answer 5

cholinergic fibers

Question 6

cholinergic fibers are present in what divisions of the nervous system?

Answer 6

somatic and ANS

Question 7

what is a cholinergic agonist?

what are the 2 types of cholinergic agonist? define them

Answer 7

Drugs which mimic or increases the actions of ACh

1. Direct Cholinergic Agonists: drugs that act at receptors
2. Indirect Cholinergic Agonists: drugs that inhibit the metabolism of Ach and increase its level in synapses and increases the actions of ACh

Question 8

what are the Direct cholinergic agonists drugs?

Answer 8

1. Bethanechol
2. Carbachol
3. Methacholine
4. Pilocarpine

Question 9

what are the Indirect cholinergic agonists drugs?

Answer 9

1. Neostigmine
2. Physostigmine
3. Pyridostigmine
4. Edrophonium
5. Tacrine
6. Donepezil
7. Ecothiophate
8. Malathion
9. Parathion
10. Sarin

Question 10

what indirect cholinergic agonist gets used in alzheimer’s?

Answer 10

Tacrine, Donepezil

Question 11

what indirect cholinergic agonist are used as insecteside?

Answer 11

Malathion, Parathion

Question 12

what indirect cholinergic agonist is used as nerve gas?

Answer 12

sabrin

Question 13

why does Acetylcholine have no clinical use?

Answer 13

Because of non-specific actions & rapid inactivation by acetylcholinesterases

Question 14

Methacholine is used to diagnose what? what do you call the test?

What type of action does it have? (does it bind muscarinic or nicotinic receptors more?)

Answer 14

bronchial asthma

methacholine challenge test

It has strong Muscarinic action & least or no Nicotinic action

Question 15

what are the therapeutic uses of Bethanechol?

Answer 15

1. Paralytic ileus: condition characterised by reduced bowel movements. mostly seen in post-op patients
2. Urinary retention: Typically seen in postoperative patients and many other neurological diseases

Question 16

what is Pilocarpine?

what type of receptor does it utilize?

is it water or lipid soluble?

what organ does it penetrate easily?

what are its therapeutic uses?

Answer 16

an alkaloid

It has Muscarinic activity only

lipid soluble

cornea

1. glaucoma
2. Sjogren syndrome: xerostomia (dry mouth), dry eye (keratoconjunctivitis) and arthritis

Question 17

what Indirect Cholinergic agonists are reversible?

Answer 17

• Neostigmine
• Physostigmine
• Pyridostigmine
• Edrophonium
• Tacrine
• Donepezil

Question 18

what Indirect Cholinergic agonists are irreversible?

Answer 18

• Ecothiophate
• Malathion
• Parathion
• Sarin

Question 19

how long do reversible enzyme inhibitors act?

how long do irreversible enzyme inhibitors act?

of the irreversible indirect cholinergic agonist list, which one is used clinically? for what is it used?

Answer 19

short period of time

long period of time

Ecothiopate, is used for glaucoma

Question 20

what drugs are used in sjogren, alzheimers, glaucoma?

what category are these? (reversible or irreversible?)

what drug is used in glaucoma? why?

Answer 20

pilocarpine and donepazil/tacrine

Reversible Cholinesterase inhibitors

Physostigmine, it penetrates the cornea well due to lipid solubility

Question 21

why cant neostigmine be used in the treatment of glaucoma?

Answer 21

it is lipid insoluble and cant penetrate cornea too well

Question 22

what is the mechanism of action of physostigmine?

Answer 22

reversible inhibition of AChE enzyme (↑ Ach)

Question 23

what acetyl cholinesterase inhibitors are used in the treatment of myasthenia gravis?

which do you use only to diagnose myasthenia gravis?

Answer 23

1. Neostigmine
2. Pyridostigmine

Edrophonium

Question 24

when is neostigmine used in Myasthenia gravis?

when is pyridostigmine used in myasthenia gravis?

when is Edrophonium used in myasthenia gravis?

Answer 24

it is used in acute cases

maintenance/ long term therapy due to longetivity of drug

shortest acting drug, so it is used in diagnosis of M. Gravis

Question 25

how do you differentiate myasthenic crisis and cholinergic crisis? what is another name for the test used to differentiate myasthenic crisis and cholinergic crisis?

Answer 25

use Edrophonium in small amount and there is contraction of muscle then it is myasthenic crisis since in cholinergic crisis the muscles would be more flaxid and not respond tensilon test

Question 26

If drug therapy is inadequate during myasthenic crisis, patients develop what? what happens If excessive amounts of drugs have been used in patients with cholinergic crisis?

Answer 26

severe muscle weakness. patients may become paradoxically weak because of nicotinic depolarizing blockade of the motor end plate.

Question 27

what is belladona poisoning? what symptoms can be seen?

Answer 27

the same thing as atropine poisoning, blocking muscarinic receptors tachycardia, constipation, dry eye, dry mouth, urinary retention, dilated pupils

Question 28

Tacrine, Rivastigmine and Donepezil, Malathion, Parathion...of these, which is used in the treatment of alzheimer's? what about the other 2 options? what type of drug is the answer for the first question?

Answer 28

Tacrine, Rivastigmine and Donepezil they are used as insectisides irreversible acetylcholinesterase inhibitor

Question 29

what are organophosphates? signs and symptoms of organophosphate poisoning are due to what? symptoms occur due to what? what are the symtoms of organophosphate poisoning?

Answer 29

irreversible cholinesterase inhibitors Phosphorylation (irreversible inhibition ) of the enzyme resulting in excess acetylcholine stimulation of muscarinic receptors miosis, blurred vision, bradycardia, salivation, sweating, urination, bronchial constriction, vomiting, and diarrhea

Question 30

what is the drug of choice for organophosphate poisoning? why? what is the problem of giving atropine alone? what is given as well during Org. Phosphate poisoning?

Answer 30

Atropine a muscarinic receptor blocker is used to control signs of muscarinic excess stimulation of OP compounds. * it cannot control the nicotinic effects OP poisoning * can't reverse the CNS effects Pralidoxime: a Acetylcholine esterase reactivator that acts by hydrolysing (reactivating) the drug bound enzyme

Question 31

what are the symptoms of Org. Phosphate poisoning?

Answer 31

DUMBELSS * Diarrhea, Abdominal cramps, vomiting, * Urination * Miosis * Bradycardia * Bronchospasm * Excitation of Skeletal muscle * Lacrimation * Salivation * Sweating