Drug Receptor Function Flashcards
How is acetylcholine synthesized? By what enzyme?
Synthesized from acetyl CoA and choline by choline acteyltransferase
What is the rate limiting step of ACh synthesis?
Getting choline into the nerve
How is ACh degraded? Into what products? By what enzyme? Where is the enzyme located?
ACh is degraded into acetic acid and choline by acteylcholinesterase located on the post-synaptic cell membrane
What is the relative affinity for ACh to the nicotinic and muscarinic receptors?
Equal
What are the muscarinic receptor subtypes and their location?
M1: Neuronal CNS/ ANS Presynaptic; M2: Cardiac; M3: Smooth Muscle and Glands and Vascular endothelium
What are the classes of direct-acting cholinergic receptor agonists?
Choline esters and alkaloids
What are the classes of cholinesterase inhibitors?
Carbamates and organophosphates
What kind of drug is bethanechol? What are its uses?
Bethanechol is a choline ester muscarinic agonist used to prevent acute postoperative or postpartum non-obstructive urinary retention
What kind of drug is carbachol? What are its uses?
A choline ester muscarinic and nicotinic agonist used to produce miosis during ocular surgery
What kind of drug is pilocarpine? What are its uses?
Pilocarpine is an alkaloid selective muscarinic agonist used topically to treat glaucoma, xerostomia (dry mouth) or for Sjogren’s Syndrome
What is Sjogren’s syndrome?
An autoimmune disease associated with dryness (lack of sweating, salivation)
What kind of drug is cevimeline?
A synthetic muscarinic agonist approved for treatment of Sjogren’s syndrome
What drugs are belladonna alkaloids that are muscarinic antagonists? What are the semi-synthetic derivatives of these drugs?
Atropine and scopolamine; Ipratropium, Tolterodine, Oxybutynin
What are the symptoms of atropine overdose?
Dry, hot, red, blind, CNS problems/confusion (mad)
What kind of drug is trimethaphan? What are its uses?
Trimethaphan is a ganglionic nicotinic antagonist used to produce controlled hypotension
What are NMJ blockers used for?
To promote skeletal muscle relaxation during surgery
What drug is a long duration, non-depolarizing NMJ blocker?
Tubocurarine
What drug is a intermidiate duration, non-depolarizing NMJ blocker? Short duration?
Pancuronium; Mivacurium
Why is succinylcholine considered an NMJ blocker even though it evokes depolarization upon binding?
It activates the nicotinic NMJ receptor longer than ACh, which leads to depletion of Ca++ stores and flaccid paralysis
Is it better to use depolarizing or non-depolarizing NMJ blockers for short surgeries?
Depolarizing
What is the antidote for overdose of non-depolarizing NMJ blocking agents? What kind of drug is it?
Neostigmine; AChE inhibitor
What is the antidote for neostigmine overdose?
Tubocurarine
What cholinergic drug can cause life-threatening hyperkalemia or malignant hyperthermia? What drug can be used to treat the malignant hyperthermia?
Succinylcholine; Dantolene
How does Botox or Botulinum toxin work?
It cleaves SNARE proteins involved in the exocytosis of ACh vesicles, inhibiting the release
What are the different categories of Cholinesterase inhibitors?
Short-acting (non-covalent inhibitors); Medium-duration (reversible carbamates); and Long-duration (‘irreversible organophosphates’)
What kind of drug is edrophonium? What is it used for?
A very short acting, non-covalent, cholinesterase inhibitor used as a diagnostic agent for Myasthenia Gravis
What are examples of carbamates that bind to the esteratic site of AChE?
Physostigmine, Neostigmine, and Pyridostigmine
What is the drug of choice to treat poisoning with atropinic agents?
Physostigmine
Which of the reversible carbamates readily penetrates the CNS? What conditions is it used to treat?
Physostigmine; Alzheimer’s and dementia
What are Neostigmine and Pyridostigmine used to treat?
Myasthenia gravis or glaucoma
What is the antidote used for overdose of organophosphate cholinesterase inhibitors?
2-PAM
