Serotonin Agonists and Antagonists Flashcards by Tesla Trooper

Carcinoid syndrome is an unusual manifestation of carcinoid tumor, a neoplasm of __________ cells.

enterochromaffin

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___________, an orally active hydroxylase inhibitor, has been approved for the treatment of diarrhea due to carcinoid tumor

Telotristat ethyl

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__________ serves as a precursor of melatonin

serotonin

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5-HT is concentrated in vesicles by a vesicle-associated transporter (VAT) that is blocked by ____________

reserpine

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The 24-hour excretion of 5-HIAA can be used as a diagnostic test for ___________

carcinoid tumor

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__________ must be prohibited during such

diagnostic tests

Bananas or food having serotonin and precursors

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__________, a 5-HT1A agonist currently in clinical trials, appears to have some antinociceptive action at higher doses while reversing opioid-induced respiratory depression

Repinotan

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_________ receptors in the gastrointestinal tract and in the vomiting center of the medulla participate in the vomiting reflex

5-HT3

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Serotonin is a potent _________ (stimulant/inhibitor) of pain and itch sensory nerve endings

stimulant

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What is Chemoreceptor reflex (Bezold-Jarisch reflex)?

Activation of 5-HT3 receptors on these afferent

vagal nerve endings leading to marked bradycardia and hypotension

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The bradycardia in chemoreceptor reflex is mediated by vagal outflow to the heart and can be blocked by __________

atropine

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A cardiac glycoside, oubain can also _________ (activate/ inhibit) the chemoreceptor reflex

activate

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Administration of _______ blockers appears to reduce skeletal muscle spasm following spinal cord injury

5-HT2

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Serotonin can cause bronchoconstriction when acts on ________ receptors.

5-HT2A receptors

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Serotonin may also cause ___________ (hypoventilation/hyperventilation) as a result of the chemoreceptor reflex or stimulation of bronchial sensory nerve endings

hyperventilation

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Serotonin can also elicit reflex bradycardia by activation of __________ receptors on chemoreceptor nerve endings

5-HT3

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What is responsible for the flush that is observed after serotonin administration or release from a carcinoid tumor?

Serotonin constricts veins, and venoconstriction with increased capillary filling leading to the flush

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Prolonged elevation of the blood level of serotonin (which occurs in carcinoid syndrome) is associated with ______________, which may result in valvular or electrical malfunction

subendocardial fibroplasia

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Why serotonin in high levels affecting heart?

Serotonin has small direct positive chronotropic

and inotropic effects on the heart

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Serotonin causes blood platelets to aggregate by activating _________ receptors

5-HT2

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Increasing tone and peristalsis are caused by the direct action of serotonin on ______ smooth muscle receptors on GI tract.

5-HT2

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Activation of _______ receptors in the enteric nervous system causes increased acetylcholine release and thereby mediates a motilityenhancing or “prokinetic” effect.

5-HT4

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How does cisapride work?

Activation of 5-HT4 receptors by cisapride in the enteric nervous system causes increased Ach release and thereby mediates a prokinetic effect

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Overproduction of serotonin in carcinoid tumor is associated with severe ________ (constipation/diarrhea)

diarrhea

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_______ receptors are present on skeletal muscle membranes

5-HT2

Serotonin syndrome is associated with skeletal muscle ___________ (contractions/relaxations)

contractions

Serotonin syndrome is associated with skeletal muscle contractions which are precipitated when _________ inhibitors are given with serotonin agonists

MAO inhibitors

Hyperthermia of serotonin syndrome results from excessive muscle __________

contraction

_______, a 5-HT1A agonist is given as an anxiolytic

Buspirone

Appetite suppression appears to be associated with agonist action at _______ receptors in the central nervous system

5-HT2C

Dexfenfluramine, a selective 5-HT agonist, was widely used as an __________ but was withdrawn because of cardiac valvulopathy

appetite suppressant

____________, a 5-HT2C agonist, is approved by the FDA for use as a weight-loss medication

Lorcaserin

The 5-HT1D/1B agonists (triptans) are used almost exclusively for _______________

migraine headache

Migraine is in two forms, classic and common. | What is the difference between the two?

Classic Migraine: Aura followed by a severe throbbing unilateral headache that lasts for a few hours to 1–2 days. Common migraine: Severe throbbing unilateral headache that lasts for a few hours to 1–2 days but NO AURA

What is aura?

Nausea, vomiting, visual scotomas or even hemianopsia, and speech abnormalities or any warning sensation

Migraine involves the _________ nerve distribution to intracranial (and possibly extracranial) arteries

trigeminal

Trigeminal nerve release three vasodilators that act on extra and intracranial arteries. What are the vasodilators?

Substance P Neurokinin Calcitonin gene related peptide

What happens when arteries dilate in migraine patients?

Extravasation of plasma and plasma proteins into the perivascular space is found in biopsy specimens from migraine patients. This causes perivascular edema

What causes headache in migraine patients?

The mechanical stretching caused by this perivascular | edema may be the immediate cause of activation of pain nerve endings in the dura

What is the mechanism of action of triptans for treating migraine?

1. Triptans activate 5-HT1D/1B receptors on presynaptic trigeminal nerve endings to inhibit the release of vasodilating peptides 2. Vasoconstrictor actions of direct 5-HT agonists (the triptans and ergot) may prevent vasodilation and stretching of the pain endings

How do antidepressants or antiseizure drugs work to stop migraine?

antiseizure agents may suppress excessive firing of | these trigeminal nerve endings

Serotonin norepinephrine reuptake inhibitors (SNRIs) and selective serotonin reuptake inhibitors (SSRIs) are used to treat ____________

clinical depression

What can trigger headache?

alcohol, chocolate, and stress

Most commonly, aura is _______ (visual/audible)

visual (flashes, zigzag lines, and glare)

Aura occur approximately 20 to 40 minutes _______ (before/after) headache pain begins

before

________ (Men/Women) are threefold more likely to experience migraine.

Women

The hypoperfusion persists throughout the ________ (aura and headache phase/aura phase only/headache phase only) in migraine.

aura and headache phase

Patients who have migraine without aura ___ (do/do not) show hypoperfusion

do not

Acute treatment for migraines can be classified as?

Nonspecific | Migraine specific

What are the nonspecific treatment for migraine?

Analgesics (NSAIDs) Antiemetics (prochlorperazine) to control vomiting Opioids (when no other thing is working)

Migraine-specific therapy includes _________ and ___________, which are 5-HT1B/1D receptor and 5-HT1D receptor agonists

triptans and ergot alkaloids

Rate the severity of nausea that occurs with use of: a. dihydroergotamine>triptans b. dihydroergotamine

dihydroergotamine>triptans | More nausea w/ dihydroergotamine

Rate the severity of vasoconstriction that occurs with use of: a. ergotamine>triptans b. ergotamine

a. ergotamine>triptans | More vasoconstriction w/ ergotamine

sumatriptan is also available in a combination product with ____________

naproxen

The onset of the parenteral drug sumatriptan is | about _____ minutes

Headache commonly recurs within _______ hours after a single dose of sumatriptan, but in most patients, a second dose is effective in aborting the headache.

24 to 48 hrs

Sumatriptan elimination half-life is of ________

2 hours

__________ is the longest-acting triptan

Frovatriptan

Triptans ________ (can/cannot) be administered to patients with risk factors for coronary artery disease

cannot

What are the adverse effects of triptans?

Pain and pressure sensations in the chest, neck, throat, and jaw Dizziness and malaise

_________ and __________ (triptans) are contraindicated in patients with severe hepatic or renal impairment or peripheral vascular syndromes

Naratriptan and eletriptan

___________ (triptan) in patients with peripheral vascular disease

Frovatriptan

__________ (triptan) in patients with Wolff-Parkinson-White syndrome

Zolmitriptan

Tegaserod, a 5-HT4 partial agonist, is used for ___________ with constipation

irritable bowel syndrome

__________ is an example of SSRI used for depression

Fluoxetine

Serotonin ________ (synthesis/metabolization) can be inhibited by p chlorophenylalanine and p-chloroamphetamine but too toxic

synthesis

Why reserpine isn't used in carcinoid tumor?

1. Sympatholytic effects | 2. High levels of circulating serotonin that result from release

_____________ has a long-lasting blocking action at 5-HT2 receptors

Phenoxybenzamine

_________ (histamine/ergot alkaloid) is partial agonists at serotonin receptors

ergot alkaloid

_____________ is a potent H1-receptor antagonist, 5-HT1 and 5-HT2 receptors blockers but has no effect on gastric secretions like histamine has.

Cyproheptadine

What is cyproheptadine used for?

Sedation (antimuscarinic effect) Diarrhea and intestinal spasms (carcinoid syndrome; postgastrectomy dumping syndrome) Smooth muscle manifestations of cold induces urticaria

_____________also appears to reduce muscle spasms following spinal cord injury, in which constitutive activity of 5-HT2C receptors is associated with increases in Ca2+ currents leading to spasms

Cyproheptadine

Ketanserin blocks _______ receptors on smooth muscle

5-HT2

Ketanserin potently blocks vascular ____ adrenoceptors

α1

___________ is used in the prevention of nausea and vomiting associated with surgery and cancer chemotherapy

Ondansetron (5-HT3 antagonist)

Valvulopathy, which may lead to pulmonary hypertension, is linked to _________ receptors

5-HT2B

_____________ is a serotonin agonist with selectivity for the 5-HT2C serotonin receptor

Locaserin

What is locaserin used for?

Appetite suppressant

Locaserin ______ (is/is not) recommended in severe renal impairment

is not

What is the mechanism of action of Locaserin?

Activation of 5HT2C stimulates proopiomelanocortin (POMC) neurons, which activate melanocortin receptors, thereby causing a decrease in appetite

If a patient does not lose at least ______ of his or her body weight after 12 weeks of use, locaserin should be discontinued

What are the adverse effects of locaserin?

``` Nausea headache dry mouth dizziness constipation lethargy mood changes suicidal ideation serotonin syndrome neuroleptic malignant syndrome ```

Individuals with a history of _______ failure should use locaserin with caution

heart (due to valvulopathy)

We should not use locaserin w/?

SSRIs SNRIs MAOIs

Valvulopathy has been associated with the use of ___ receptor agonists

5-HT2B

________ receptors are involved in thermoregulation, learning memory, and nociceptive processing

5-HT7

_______ receptor mediates hallucinogenic effects

5-HT2