21 Questions
Why is protection needed for muscarinic agonists, but not the natural ligand acetylcholine?
The muscarinic agonists enter the body from outside. This makes them vulnerable to ubiquitous esterases. Therefore, the drug must be protected. ACh is localized in the synapse and will not contact any esterases - therefore no protection needed.
Which drug mimics ACh and binds to the cholinergic receptor?
Muscarinic Agonist
Which drug binds to the cholinergic receptor, but produces no signal transduction?
Muscarinic Antagonist
What should happen in order to increase a drug's half-life?
Make it necessary for the drug to travel from the target to the liver, where harsh phase 1 or 2 drug rxns will occur
What should happen to further increase the half-life of a drug which already requires hepatic metabolism?
Add an EWG (like F) to protect the drug from hepatic metabolism
Which of the following is NOT something that the nature of the amine determines?
Localized - protected or unprotected
What does an alkyl linker provide?
A defined distance between the amine and ester required for binding to a receptor
What is a difference between Muscarinic Agonist vs. Antagonist structures?
Muscarinic Antagonists all have an aromatic ring
What change can occur to ACh so the resulting compound exhibits agonistic activity?
The area between the amine and ester can be bulkier than in ACh
What change can NOT occur to ACh so the resulting compound exhibits antagonist activity?
Cleave the ester by esterases, which will allow for more things to attach to the structure
What kind of biological effect will acetylcholinesterase inhibitors have?
The same as cholinergic agonists
What is the makeup of the anionic site of mAChR?
It contains an Asp, which enables an ionic bond to form between negatively charged Asp and positively charged quaternary amine of ACh
What is the makeup of the 'anionic' site of AChE?
Contains Trp, which enables a pi-cation interaction between resonating pi-electrons of the aromatic ring of Trp and positively charged quaternary amine of ACh
Why is echothiopate suitable for application in humans?
It is the only irreversible AChEI which contains a quaternary amine, preventing it to reach the CNS
Match the following regarding measures in the metabolism of malathion that are exploited.
True = The insect specific P=O bond required to activate drug (only in insects) False = The insects are not able to metabolize any kind of drug, making it useless True = Metabolism by esterases, which prevent drug from reaching CNS False = Metabolism by liver, which helps the drug to have better bioavailability
Why can ProPam pass the BBB in contrast to 2-PAM?
ProPam does not contain permanent positive charge of the aromatic quaternary nitrogen in 2-PAM
The electrophilicity of the phosphorous prevents the hydrolysis of the phosphorylated serine, which stops the regeneration of the enzyme - is the reaction why organophosphate AChEIs into quasi-irreversible inhibitors?
True
Which CYP enzyme is responsible for N-dealkylation and aromatic hydroxylation?
CYP3A4
Which enzyme is responsible for converting a tertiary amine to an N-oxide?
FMO
Which CYP enzyme is responsible for demethylation of methoxy group to phenol?
CYP2D6
What slows down the AChE reaction time?
A tertiary carbamate
Explore why protection is required for muscarinic agonists but not for the natural ligand acetylcholine in this quiz. Understand the differences that necessitate safeguarding muscarinic agonists in medical applications.
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