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17 Cards in this Set
- Front
- Back
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5-HT1 receptors
Describe mechanism of action Location |
Mechanism: GCPR's; hyperpolarize by increasing K conductance
Location: brainstem, basal ganglia |
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5-HT2 receptors
Describe mechanism of action Location |
Mechanism: GPCR's; depolarize by decreasing K conductance
Location: prefrontal cortex |
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5-HT3 receptors
Describe mechanism of action Location |
Mechanism: direct action; rapid depolarization due to Na gating
Location: brainstem, GI tract |
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List the 5 sites of action for 5-HT (as discussed in class)
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(1) Enterochromaffin cells
(2) Platelets (3) Heart (4) GI tract (5) CNS |
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Effects of 5-HT on:
(1) Enterochromaffin cells (2) Platelets (3) Heart (4) GI tract (5) CNS |
(1) Enterochromaffin cells: 5-HT secreted due to luminal stretching & causes smooth mm contraction
(2) Platelets: 5-HT released due to injury; causes local vasospasm (3) Heart: complex responses but overall produce positive inotropic & chronotropic effects (4) GI: see enterochromaffin cells; cause enhanced motility (5) CNS: 5-HT cell bodies in brainstem & project throughout the brain; impt in psychosis & behavioral disorders |
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Buspirone
Mechanism of action Type of agent Therapeutic use |
Buspirone
Mechanism: 5-HT1 agonist (hyperpolarizing) Type: antianxiety Therapeutic use: anxiolytic & smoking cessation |
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Tryptans
Mechanism of action Prototype Toxicity Therapeutic use |
Tryptans
Mechanism: 5-HT1 agonist (hyperpolarizing) Prototype: sumatryptain Toxicity: heart block & coronary spasm Therapeutic use: migraine treatment |
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Ergot & Ergot Alkaloids
Mechanism of action Prototype Toxicity Therapeutic use |
Ergot & Ergot Alkaloids
Mechanism: 5-HT & alpha agonists Prototype: ergotamine Toxicity: cardiac valvular lesions & retroperitoneal fibrosis Therapeutic use: formerly for migraines but now replaced by tryptans |
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What are the 2 prototype drugs (discussed in class) that are anti-migraine agents?
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(1) sumatryptan
(2) ergotamine |
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LSD
Mechanism Type of agent Therapeutic use |
LSD
Mechanism: 5-HT agonist w/ high affinity Type: hallucinogenic agent Therapeutic use: none |
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Name the 5-HT receptor agonists.
Name the 5-HT receptor antagonists. |
5-HT agonists:
Buspirone Sumatryptan Ergotamine LSD 5-HT antagonists: Ketanserin Ondansetron Ritanserin Atypical antipsychotics |
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Ketanserin
Mechanism of action Toxicity Therapeutic use |
Ketanserin
Mechanism: 5-HT1 and 5-HT2 antagonist Toxicity: sedation Use: anti-hypertensive |
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Ondansetron
Mechanism of action Therapeutic use |
Ondansetron
Mechanism: 5-HT3 antagonist (esp in GI tract) Use: control chemotherapy-induced emesis |
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What is the strategy behind the newer atypical antipsychotic drugs?
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combination of 5-HT blockade with classical D2 receptor blockade
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Name the drug that treats the following:
(1) Hypertension (2) Anxiety (3) Migraines (4) Chemo-induced emesis |
(1) Hypertension = ketanserin (5-HT1 and 5-HT2 antag)
(2) Anxiety = buspirone (5-HT1 agonist) (3) Migraines = sumatryptan (which has pretty much replaced ergotamine; 5-HT1 agonist) (4) Chemo-induced emesis: ondansetron (5-HT3 antag) |
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How do tryptans treat migraines (what is their mechanism)?
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Tryptans are 5-HT1 agonists therefore they stimulate serotonin receptors in the brain which causes blood vessels in the brain to contract. At the same time, it also reduces transmission of pain signals by nerves to the brain.
Prototype: sumatryptan (Imitrex) |
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Describe ondansetron's mechanism of action.
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Ondansetron is a selective 5-HT3 antagonist. The 5-HT3 receptors that it targets are located in the brainstem & GI tract.
Ondansetron's primary activity is related to blocking the GI receptors..which explains why it is used to control chemo-induced emesis. |
