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15 Cards in this Set
- Front
- Back
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Two types of Cholinergic Synapses (1,2)
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1) muscarinic: activates post-parasymp (neuro-effector junction)
2) nicotinic: -ANS and somatic NS (ganglia, somatic neuromuscular junction) -broad response |
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Biphasic ACh response (2)
"unmasking" |
-large dose is inhibitory
-muscarinics dominate, masking the nicotinic response -can be unmasked w/ muscarinic blocker (atropine) |
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which cholinergic receptors are more sensitive to ACh
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-muscarinic (vs. nicotinic)
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Types of cholinergic receptors in the blood (3)
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M3 (muscarinic type 3) receptor:
-not innervated -only receptive to ACh in the blood Alpha and Beta: -ARE innervated -alpha constricts, beta relaxes |
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almost all secretions are stim'ed by what NT (2)
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-ACh
-sweating included (although sympathetic) |
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general nicotinic response (3)
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-fasciculations (muscle twitching)
-blockade, muscle weakness (large dose) -can trigger sympathetics: ups heart rate, bp |
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Ach as a drug (3)
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-not good drug
-hydrolized rapidly by ACh esterases or pseudocholinesterase -action not specific |
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2 types of directly Acting Cholinergic Drugs (2,2)
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1. ACh and related choline esters:
Carbachol Bethanechol 2. Cholinomimetic alkaloids (a drug from a botanic source, Nitrogen based) Muscarine – From the Amanita buscaria mushroom Atropine blocks muscarine Has the same QA (see explanation below) group as choline Pilocarpine – From the leaves of the Pilocarpus shrub A TA, gets to brain Miotic, and can stimulate salivation |
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Indirect cholinergic drugs (4)
(Tx for?) |
-cholinesterase inhibitors
-affinity but no efficacy -can be reversible/irreversible -tx for myasthenia gravis, atropine poisoning, insecticide |
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reversible cholinesterase inhibitors (5)
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Physostigmine (eserine) – Prototype
A TA. From Calabar bean, the “Ordeal” bean Death due to paralysis of respiratory muscles 10,000 times the affinity of ACh for receptors Reversible Neostigmine A QA Anti-curare drug Often used after surgery Pyridostigmine – synthetic, short-acting Edrophonium – synthetic, short-acting Tacrine Tx Alzheimers, Dementia Boosts ACh in brain to ameliorate effects. |
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physostigmine (eserine) (4)
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-reversible cholinesterase inhibitor prototype
-a tertiary amine (TA) -death due to paralysis of respieratory m.'s -10,000x's affinity of ACh for receptors |
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Neostigmine (4)
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-reversible cholinesterase inhibitor
-quat. amine -anti-curare drug (curare=muscle relaxant) -used after surgery |
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irreversible cholinesterase inhibitors (
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-poisons
-Diisopropyl fluorophsophate (DFP) Echothiophate Isofluorphate Parathion, malathion – insecticides Parathion is metabolized to paraoxon – the real poison Malathion is harmless to humans b/c we have a liver enzyme to metabolize it. Soman, tabun, sarin – nerve gasses, developed in Germany in WWII [pralidoxime – cholinesterase enzyme reactivator] – can regenerate (antidote) if given w/I minutes or hours. [Atropine can block the muscarinic effects; a partial antidote] |
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quaternary amine (3)
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- "+" charge
-cannot pass BBB -choline is a QA |
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tertiary amine (3)
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-neutral
-CAN pass BBB - : . can have neurological effects |
