9/6/13 Flashcards
Describe how acetylcholine is formed an released. In parenthesis are the toxins that affect process.
Choline enters the nerve terminal with Na (hemicholinium)–> Acetyltransferase combines choline with acetyl CoA to form Ach–> Ach travels to vesicles and enter through an active process and H+ leaves vesicle–> nerve signal travels and leads to influx of Ca2+–> stimulates the release of vesicles (botulinium toxin inhibits, black widow spider toxin promotes)–> Ach acts and then is broken down by acetylcholinesterase
Which muscarinic receptors use a Gq receptor
1,3,5
Which muscarinic receptors use a Gi receptor
2,4
M1 receptors act where?
Gastric parietal cells
M2 receptors act where?
heart
M3 receptors act where?
Bladder, smooth muscle, exocrine glands
What are the three effector organs that use nicotinic receptors
skeletal muscle, adrenal medulla, autonomic ganglia
What happens with the constriction of the ciliary muscle during parasympathetic activation in regards to pressure of the eye?
It decreases the intraocular pressure, aqueous humor is drained out
What part of the heart is not significantly activated by the parasympathetic system?
ventricle
What are the three choline esters that bind to nicotinic receptors
Ach, Methacoline, carbachol
Why does the vasculature vasodilate during systemic parasympathetic stimulation even though blood vessels are not innervated by parasympathetic system?
Vasodilation occurs because of the M3 receptors on the endothelial cells, which activate the release of NO causing the vasodilation. If the endothelial cells are injured, Ach binds to the M3 receptors of the smooth muscle, leading to vasoconstriction
Drug used mainly to increase GI motility, decrease urine retention, and increase bladder contraction
Bethanechol
Drug used mainly to treat glaucoma, and can bind to both muscarinic and nicotinic receptors, a quartnery amine and so cannot invade the CNS
carbachol
A drug that can invade the CNS because it is uncharged and is used in emergency cases of glaucoma, can be used to treat Xerostomia
Pilocarpine
What are the three classes of cholinesterase inhibitors and which one is the most therapeutic?
Alcohols, Carbamic acid esters (most therapeutic), and organophosphates
The process when a cholinesterase breaks one of the oxygen phosphorous bonds of the inhibitor leading to an increase in the phosphorous-enzyme bond
Aging
At moderate doses, cholinesterases can (increase/decrease) peripheral resistance and blood pressure
Increase (No parasympathetic nerves on blood vessels, sympathetic ganglion are stimulated by their nicotinic receptors)
A tertiary carbamic acid, this drug can invade the CNS and is used to counteract the effects of atrophine, lowers the intraocular pressure, and can lead to convulsions
Physostigmine
A quaternary carbamic acid, this drug treats the effects of turbocurarine at the neuromuscular junction, also can treat myasthenia gravis, only in the body for about 30 min to 2hr
Neostigmine
Cholinesterase inhibtors, these drugs have similar effects to neostigmine but last longer in the body
Pyridostigmine and ambenonium (used to treat MG), demecarium (used to treat glaucoma)
A cholinesterase inhibitor that is very reversible, used as a test drug for MG, a quaternary amine, in overdoses can be treated by atropine
Edrophonium
These drugs are used to treat Alzeimer’s disease, are tertiary amines and can invade the CNS, cause gastric distress
Tacrine and donezepil
An organophosphate, it can irreversibly bind to cholinesterases, used mainly for glaucoma, can lead to cataract formation
Echothiolphate
This drug can help cholinesterase regenrate after binding to an organophosphate, as long as it has not aged
Pralidoxime
Insecticides that can act as irreversible cholinesterase inhibitors
Malathiol, Parathiol
A type of warfare gas that can be lethal because of its effects as an irreversible chlinesterase inhibitor
Sarin
