Anticholinesterases and Pesticides Flashcards

1
Q

How do cholinesterases function?

A

Serine hydrolases
Catalytic subunit splits substrate choline esters by introducing water bond
Targeted to site by structural subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Is butyrylcholinesterase vital?

A

No

Will be fine without it, won’t know if you have mutation until given succinylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which cholinesterases can be recovered by pralidoxime?

A

Acetylcholine

Cholinesterase gets inhibited by organophosphate agents, oximes can reverse it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the categories of acetylcholinesterases and are they reversible or irreversible?

A

Quaternary amines - reversible in secs
Carbamates - reversible in mins
Organophosphates - irreversible (takes hours or longer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What drugs are in the category of quaternary amines?

A

Edrophonium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What drugs are in the category of carbamates?

A

Neostigmine
Physostigmine
Pyridostigmine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What drugs are in the category of organophosphates?

A
Pesticides (malathion, diazanon, carbaryl)
Chemical warfare (soman, sarin, VX)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the mechanism by which anticholinesterases inhibit AChE?

A

Form covalent bond with active site serine
Acylate AChE
Recovery of enzyme activity depends upon deacylation (hence reversible and irreversible)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In general, what results from the use of anticholinesterases?

A

Inactivation of AChE = excess ACh = parasympathetic stimulation (DUMBBELSS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What anticholinesterases are used to treat paralytic ileus and atony of the bladder?

A

Neostigmine

often in conjunction with muscarinic agonist like bethanechol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What anticholinesterases are used to treat glaucoma?

A

Physostigmine

often in conjunction with muscarinic agonist like pilocarpine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What anticholinesterases are used to treat myasthenia gravis?

A

Neostigmine, pyridostigmine

in conjunction with muscarinic antagonist to counteract parasympathetic effects of ACh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What anticholinesterases are used to help with recovery of neuromuscular block following surgery?

A

Neostigmine

with muscarinic antagonist to counteract parasympathetic effects of ACh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What anticholinesterases are used to treat anticholinergic toxicity (e.g. atropine)?

A

Physostigmine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which organophosphate pesticide is toxic to humans?

A

Parathion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why are organophosphate pesticides lethal to insects but not to humans?

A

Metabolized slowly in insects because they lack a carboxylesterase required for rapid inactivation

17
Q

Why are nerve agents particularly deadly?

A

Nerve agents “age” extremely rapidly and once aged, cholinesterase cannot be reactivated by oximes

Aging = conversion to form that can’t be reactivated by oximes