[MEDORG-SEMIS-04-PT3] CHOLINERGIC

THIS FLASHCARDS IS ABOUT [MEDORG] CHOLINERGIC - CHOLINESTERASE INHIBTORS AND ACTIVATORS.

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NORMAL MECHANISM OF CHOLINESTERASE INHIBITORS:

Acetylcholine → hydrolyzed by AChE → acetate + choline

WHEN THE ENZYME IS INHIBITED:

• Acetylcholine accumulates

• Cholinergic transmission increases.

Reversible and Irreversible Inhibitors

What are the (2) Types of Inhibitors?

• Pyridostigmine

• Edrophonium

• Neostigmine

• Donepezil

(These form temporary interactions with the enzyme)

What are the (4) Reversible Inhibitors (Cholinesterase Inhibitors)?

Hint: PEND

Echothiophate

(These form covalent bonds with acetylcholinesterase)

What is an examples of Irreversible Inhibitors (Cholinesterase Inhibitors)?

Neostigmine

What is an example of carbamate inhibitors?

Carbamylated enzyme complex

Carbamate group forms a ____________________, slowing hydrolysis.

Echothiophate

What is an example of organophosphate inhibitors?

Phosphorylated enzyme complexes

Organophosphate Inhibitors forms ___________________ that are extremely stable.

Edrophonium

What is an example of non-covalent inhibitors?

Electrostatic interactions

Edrophonium is short-acting because it binds only by?

Donepezil

This antimuscarinic drug is a unique inhibitor used in Alzheimer’s Disease.

Structure:

• Aromatic rings

• Tertiary amine

Alzheimer’s Disease

Donepezil is used for what disease?

CNS

Donepezil is designed to penetrate the?

Pralidoxime

What is an example of cholinesterase reactivators?

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Mechanism of Pralidoxime:

Organophosphates phosphorylate acetylcholinesterase.

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Pralidoxime contains an oxime group that:

• Attacks the phosphorus atom

• Removes the phosphate group

• Restores enzyme activity

Supplemental Info Only

Structural Features of Pralidoxime:

• Quaternary ammonium group

• Oxime functional group

The groups allow:

• Binding to acetylcholinesterase

• Nucleophilic attack on phosphorus