Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/51

Click to flip

51 Cards in this Set

  • Front
  • Back
5HT is synthesized from?
Tryptophan (in diet; in 2 steps)
Describe platelets' relationship to 5HT.
They don't synthesize it, but take it up from blood (active uptake process in platelets and nerve terminals)
Highest % of 5HT is where in body?
90% in GI enterochromaffin cells; rest is in platelets and brain
Rate limiting enz for 5HT synth?
tryptophan hydroxylase
MAO inhibitors and interaction with 5HT?
Inhibit breakdown/metabolism of 5HT to 5-OH Indole Acetaldehyde (promote serotonin syndrome)
What inhibits 5HT uptake into CNS?
other amino acids
Inhibits 5HT synthesis?
p-chlorophenylalanine (irreversible)
Inhibit 5HT neuronal re-uptake?
cocaine, SSRA (fluoxetine), TCA (imipramine)
Inhibit 5HT storage, lead to 5HT depletion?
reserpine
Inhibit 5HT metabolism?
MAO inhibitors
Promote 5HT release?
p-chloroamphetamine, which then depletes overall 5HT levels
How many 5HT receptor subtypes?
at least 15, with multiple transduction mechanisms
5HT1-A?
role in anxiety/depression
5HT1-D?
role in migraine
5HT-2?
role in CNS behaviors; places more emphasis on cardiovascular role
5HT-3?
role in nausea and vomiting (esp due to chemo)
Endogenous fxns of 5HT?
Central NT
Melatonin precursor
Inc GI motility*
carcinoid tumor (inc 5HT): diarrhea, bronchoconstriction, edema
Platelets: 5HT-2 receptors-->aggregation, vasoconstriction
Pharmacological fxns of 5HT?
Respiratory: bronchoconstriction (contraindicated in asthma); stim aortic, carotid chemoreceptors and inc RR
GI: intense rhythmic contractions due to direct and indirect effects (sm intestine very 5HT sensitive)
Vagal: 5HT-3 receptors on afferents --> stim vomiting
Cardio effects of 5HT?
1. direct (immediate) large artery vasoconstriction, indirect (NO and PGI2, prolonged) vasodilation
2. Heart: direct ionotrope, chronotrope
3. Reflex mech due to change in BP
4. Stim sensory nerve endings in baroreceptors, vagal afferents --> bradycardia, hypotension (with overdose)
CNS effects of 5HT?
1. pain perception
2. sleep/wakefulness
3. behaviors (depression, schizophrenia, OCD etc)
4. neuroendocrine regulation (control hypothalamic cells involved in ant pituitary hormones)
Examples of 5HT agonists?
sumatriptan
fluoxetine
buspirone
cisapride
LSD
ergot alkaloids
MOA--sumatriptan
5HT1-D agonist; contraindicated in angina; used for migraine
MOA--fluoxetine
SSR; depression
MOA--buspirone
5HT1-A agonist; for anxiety
MOA--cisapride
5HT4 agonist; inc GI motility, dec G-E reflux (taken off market for fatal arrhythmias*)
MOA--LSD
5HT1-A; hallucinogen
MOA--ergot alkaloids
5HT1, 2 agonist
List 5HT antagonists
methylsergide, cyproheptadine
ketanserin
ondansetron
clozapine
MOA--methylsergide, cyproheptadine
5HT2 antagonists; used for carcinoid, migraines
MOA--ketanserin
5HT2, alpha antagonist; antihypertensive
MOA--ondansetron
5HT3 antagonist; for chemotherapy induced n/v
MOA--clozapine
5HT2A/2C antagonist; for schizophrenia
Sx's of common allergic rxns?
Bronchoconstriction***
(rhinitis, conjunctivitis, urticaria, dermatitis, anaphylaxis)
Release of histamine?
synth by decarboxylation of histidine; released from mast cells when stim by IgE due to foregin Ag in body
H1 receptor: location, fxn
sm muscle, endothelium, CNS;
vasodilation, bronchoconstriction, sm muscle activation, separation of endothelial cells
H2 receptor: location, fxn
parietal cells;
regulate gastric acid secretion
H3 receptor: location, fxn
CNS;
regulate release of other NTs
H4 receptor?
recently discovered, widespread (organs of digestive tract, basophils, bone marrow), unknown fxn
Describe (generally) 1st generation antihistamines
small, lipophilic (cross BBB), not specific to H1; highest sedation among antihistamines
Describe (generally) 2nd generation antihistamines
more specific to peripheral H1 receptor; less sedation than 1st gen (but when given in higher dose, will still cause sedation)
Describe (generally) 3rd generation antihistamines
metabolite derivatives or active enantiomers of prior antihistamines; safer, faster, more potent than 2nd gen (will still give sedation if given in higher dose, but less sedation than 2nd or 1st)
Pharmacokinetics of 2nd generation antihistamines?
rapid onset, half lives= loratidine 24 hrs, fexofenedine 14 hrs, cetirizine 8 hours (kids metabolize cetirizine faster; rates similar for others)
Eicosanoids overview?
Be aware that multiple classes (PGs, TXA, PGI, LT) that do opposite things (vasoconstriction vs vasodilation)
Dinoprostone
generic name for PGE-2, relax uterine sm muscle when labor is induced; to terminate pregnancy in early stages
Misoprostol
analogue of PGE-1, prevent gastric ulcers
Mediators of pulmonary HTN?
serotonin (5HT), endothelin-1 (ET)
Endothelin-1
potent vasoconstrictor; plasma levels are increased in pulm HTN
Bosentan
sulphonamide based ET-A & ET-B receptor blocker; contraindicated in pregnancy for teratogenic effects**; induces CYP2C9, CYP3A4
Sitaxentan
sulphonamide based selective ET-A antagonist (ET-A:ET-B 6500:1); CYP2C9 metabolism-->interacts with warfarin
MC adverse fx's with sitaxentan?
headache, constipation, dizziness, insomnia
Ambrisentan
non-sulphonamide ET-A moderately selective (260:1) antagonist; no interaxn w coumarin based anticoagulants