Pharmacology - chapter 4 - Cholinergic agonists Flashcards

0
Q

In Ach synthesis Acetyl CoA is supplied by?

A

the mitochondria

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1
Q

rate-limiting step in Ach synthesis?

A

uptake of choline by sodium/choline co-transporter

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2
Q

What drug inhibits the Na/Choline co-transporter?

A

Hemicholonium

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3
Q

How is Ach stored?

A

In the vesicles of presynaptic neurons, together with ATP and proteoglycans

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4
Q

Degradation of Ach occurs…. ?

A

in the synaptic cleft by acetylcholinesterase and butyrylcholinesterase in plasma

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5
Q

What is muscarine?

A

an alkaloid present in certain poisonous mushrooms

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6
Q

Locations of muscarinic receptors?

A

Ganglia of peripheral nervous system and on effector organs such as smooth muscle, brain, heart, exocrine glands etc..

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7
Q

What kind of G-protein are M1 and M3 receptors coupled with?

A

Gq - protein that activates Phospholipase C

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8
Q

Pirenzepine … ?

A

is a tricyclic anticholinergic drug that inhibit M1 muscarinic receptors

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9
Q

Darifenacin is … ?

A

a competitive muscarinic blocker with affinity for M3 receptors. Used for treating overactive bladders.

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10
Q

One action that limits the clinical usefulness of direct acting cholinergic agonists?

A

They show little specificity

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11
Q

Bethanecol … ?

A

have strong muscarinic activity. Primarily working on intestinal motility and tone, and on the detrusor muscle of the bladder. Used in post-partum urinary obstruction.

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12
Q

Carbachol?

A

have both nicotinic and muscarinic actions. Profound effects on cardiovascular and GI systems. Used as miotic agent to treat glaucoma.

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13
Q

Pilocarpine.. ?

A

Muscarinic activity. One of the most postent stimulators of secretions(secretagogue), and therefor used to treat xerostomia and Sjøgrens yndrome. Stable to AChE.

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14
Q

Pilocarpine in glaucoma?

A

drug of choice in the emergency lowering of intraocular pressure of both open-angle and closed-angle glaucoma. Mechanism: opens the trabecular meshwork around the canal of schlem.

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15
Q

Indirect-acting cholinergic agonists?

A

work by inhibiting Acetylcholinesterases

16
Q

two broad classes of AChE inhibitors?

A

short acting and long acting

17
Q

Edrophonium.. ?

A

short-acting AChE inhibitor used in the diagnosis of myasthenia gravis. Duration of action is 10-20 minutes.

18
Q

antidote in a cholinergic crisis?

A

atropine

19
Q

Physostigmine…?

A

Intermediate-acting indirect inhibitor of AChE. work on both muscarinic and nicotinic receptors, as well as the NMJ. Also used in treatment of anticholinergic overdoses with atropine, phenothiazines and trycylic antidepressants.

20
Q

Neostigmine.. ?

A

Synthetic compound. More polar and therefor absorbed poorly from the GI-tract. Used to stimulate the detrusor muscle and as antidote for tubocurarine poisoning.

21
Q

donepezil, rivastigmine and galantamine are used to treat…?

A

Alzheimer disease

22
Q

What is the pathomechanism regarding ACh in Alzheimer?

A

Loss of cholinergic neurons in the nucleus basalis of maynert

23
Q

Echothiophosphate..?

A

Bind covalently to a serine -OH group at the active site of AChE.

24
Q

What is “aging”?

A

When irriversible AChE inhibitors bind to AChE, the enzyme slowly loses an alkyl group, rendering it useless

25
Q

Pralidoxime..?

A

reactivate inhibited AChE. This must occur before aging has happened

26
Q

Pralidoxime and CNS?

A

naut. Pralidoxime cannot penetrate BBB.

27
Q

AChE inhibitors are typically associated with ………. bowel activity

A

AChE inhibitors are typically associated with increased bowel activity

28
Q

what is cycloplegia?

A

paralysis of the ciliary muscle with problem focusing on near objects.

29
Q

which one is more toxic in humans, parathion or malathion?

A

Parathion

30
Q

Describe the difference in the molecular structure of neostigmine and physostigmine?

A

Neostigmine is a quarternary(charged) substance and cannot enter CNS

Physostigmine is a tertiary(uncharged) substance and readily enters CNS