24 Questions
Which receptor type is primarily targeted by cholinomimetic drugs?
Nicotinic receptors at ganglia
What is the abbreviation for acetylcholine?
Ach
Which part of the nervous system is abbreviated as 'ANS'?
Autonomic nervous system
What do cholinomimetic drugs primarily aim to mimic?
Cholinergic stimulation
What is the drug of choice for a patient complaining of both complete ileus and difficulty in urination?
Bethanechol
Which drug would be most appropriate for the management of paralytic ileus, atony of the GIT smooth muscle, and urinary retention?
Neostigmine
In the case of insecticide poisoning with symptoms including convulsions and mydriasis, which drug would be most suitable for treatment?
Atropine
Which cholinergic agonist is poorly absorbed and has no distribution into the CNS?
Bethanechol
What is the drug of choice for the management of glaucoma?
Echothiophate
Which drug is used for the diagnosis of myasthenia gravis?
Edrophonium
Which cholinomimetic drug has a half-life of approximately 100 hours?
Echothiophate
Which cholinergic agonist is administered by oral, subcutaneous, and topical routes?
Bethanechol
What type of drugs impact the ffi receptor through the action of Ach receptors?
Indirect-acting drugs
Which enzyme prevents the metabolism of Ach, prolonging its effects?
Acetylcholinesterase (AChE)
What is the primary function of acetylcholinesterase?
Terminating the effects of Ach
Which type of inhibitors reversibly compete for ACh binding at the anionic site of AChE?
Short-acting competitive inhibitors
Which type of inhibitors contain a carbamyl ester linkage that carbamylates the AChE for a relatively longer time?
Medium-acting carbamate inhibitors
Which cholinesterase reactivator can free the AChE enzyme from the organophosphorus-cholinesterase complex if the complex has not aged?
Pralidoxime
Why is Pralidoxime ineffective in reversing the CNS effects of organophosphate poisoning?
It cannot cross the blood-brain barrier
What is responsible for a significant number of emergency visits due to poisoning?
"Echothiophate and organophosphates"
"Acetylcholine is a non-selective endogenous ligand for both nicotinic and muscarinic receptor types." - True or False?
"True"
Which type of receptors are activated by cholinergic drugs and belong to the G-receptor family?
Muscarinic receptors
Which long-acting cholinergic drug is not hydrolyzed by AchE and can lead to severe poisoning symptoms such as hypertension?
Pilocarpine
Which drugs will be discussed in subsequent lectures along with cholinergic agonists and antagonists?
Cholinesterase inhibitors
Study Notes
- Ifti Act refers to indirectly acting drugs that impact the ffi receptor through the action of Ach receptors.
- Acetylcholinesterase (AChE) inhibitors prevent the metabolism of Ach, prolonging its effects. Examples include: Edrophonium, donepezil, galantamine, and physostigmine.
- Acetylcholinesterase inhibitors prevent the metabolism of Ach, prolonging the effects of Ach activation.
- Acetylcholinesterase is an enzyme richly found in cholinergic synapses, terminating the effects of Ach within milliseconds.
- Short-acting competitive inhibitors, such as Edrophonium, donepezil, and galantamine, reversibly compete for ACh binding at the anionic site of AChE.
- Medium-acting carbamate inhibitors, such as physostigmine and neostigmine, contain a carbamyl ester linkage that carbamylates the AChE for a relatively longer time.
- Long-acting inhibitors, such as echothiophate and organophosphates, contain a phosphate group that covalently binds to the esteric site of the AChE.
- Pralidoxime, a cholinesterase reactivator, can free the AChE enzyme from the organophosphorus-cholinesterase complex if the complex has not aged.
- Pralidoxime is ineffective in reversing the CNS effects of organophosphate poisoning due to its inability to cross the blood-brain barrier.
- Cholinesterase inhibitors, including insecticides and nerve gases, are responsible for a significant number of emergency visits due to poisoning.
- Cholinergic drugs, including cholinergic agonists and antagonists, will be discussed in subsequent lectures.
- Acetylcholine is a non-selective endogenous ligand for both nicotinic and muscarinic receptor types.
- Muscarinic receptors belong to the G-receptor family and are activated by cholinergic drugs.
- Nicotinic receptors are ion channel receptors and are also activated by cholinergic drugs.
- Pilocarpine and muscarine are long-acting cholinergic drugs that are not hydrolyzed by AchE and can cross the blood-brain barrier, leading to severe poisoning symptoms such as hypertension with pilocarpine.
Test your knowledge on drugs acting on the cholinergic or parasympathetic arm of the autonomic nervous system (ANS) with this quiz. Explore cholinomimetics, their mechanisms of action, and their effects on various physiological systems.
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