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Pharmacology Exam 6
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Serotonin
5-Hydroxytryptamine
autocoid
neurotransmitter in CNS and enteric nervous system
local hormone that modulates GI activity
Serotonin is stored in
entero-chromaffin cells of the gut and CNS
5-HT metabolized by ___ and ____ to ____, which is extreted in the urine and is used to measure excess 5-HT production
monoamine oxidase and aldehyde dehydrogenase
product is 5-HIAA which can be measured in the urine
Patients with ____ will excrete large amounts of 5-HIAA
malignant carcinoid
# of serotonin receptors
7
5HT1 agonists
sumatriptan
5HT2 antagonists
ketanserine
cyproheptadine
ergot alkaloids
5HT3 antagonists
ondansetron
yellow circumscribed tumor that occurs in the small intestine, appendix, stomach or colon
carcinoid
releases a lot of 5-HT
5-HT is released by platelets during
aggregation
5-HT causes vasoconstricion by stimulating _____ receptors. This can be blocked by ____.
5HT2
ketanserine
5-HT causes vasodilation by stimulating ____ receptors.
5HT1
5-HT causes ____ and _____ by interacting with both 5HT1 and 5HT3 receptors
positive inotropic and chronotropic effects
Other actions of 5HT
increase GI motility
cause uterine contractions
cause bronchial contractions
5HT3 receptor
not g protein coupled
Na+/K+ channel
Ketanserine
5HT1c antagonist
5HT2 antagonist
alpha1-adrenergic antagonist
alpha 1 adrenergic receptor antagonist
ketanserine
lowers blood pressure
Methysergide receptor and uses
5HT1 antagonist
migraine prophylaxis
vascular headaches
horton's syndrome
ineffective for active migrane
toxicity limits use
cyproheptadine receptors and uses
5HT2 blocker
H1 blocker
muscarinic cholinergic blocker
treatment of post gastrectomy dumping syndrome
intestinal hypermotility in carcinoid tumor
Buspirone receptor and use
5HT1A agonist
non-benzodiazepine anxiolytic
sumatriptan receptor and uses
5HT1D partial agonists
accute migrane and cluster headache
cAMP contraction of arterial smooth muscle, esp in carotid and cranial circulation
PO, SC and Nasal spray
drug of choice for sever migraine headaches with n/v
Cisapride receptor and uses
5HT4 agonist
compassionate use in GERD and motility disorders
Tegaserod receptor and uses
5HT4 patial agonist
for IBS with constipation
Antagonists of the 5HT3 receptor
ondansetron
granisetron
tropiseron
batanopride
Uses of 5HT3 receptor antagonists
control n/v resulting from intestinal vagal nerve and central CTZ stimulation from surgery or chemo/radio therapy
major side effects of 5HT3 antagonists
headache
constipation
Clozapine receptor and use
5HT2 blocker
antipsychotic agent
little or no extrapyramidal side effects
Bradykinin
nona-peptide derived from kininogens
Kallindin
decapeptide derived from kininogens
involved in synthesis of bradykinin and kallidin
tissue and plasma kallikreins
synthesis and metabolsm of kinins
catabolized my kininase II (ACE)
short 15 sec t1/2
HMW kininogen + Plasma kallkrein =>
bradykinin
LMW kininogen + tissue kallikreins =>
kallidin
Breaks down bradykinin and kallidin to inactive fragments
kinases I and II
changes kallidin into bradykinin
aminopeptidases
Three kinins identified in mammals
bradykinin
lysylbradykinin (kallidin)
methionyllysylbradykinin
all contain bradykinin
Physiological action of bradykinin and kallidin as autocoids
increase vascular permeability
produce vasodilation
increase synthesis of prostaglandins
cause pain and edema
Bradykinin and kallidin contribute to pathogenesis of
inflammatory diseases such as allergis, arthritis, asthma, sepsis, IBD, rhinitis
four classis symptoms of inflammation produced by bradykinin
redness
heat
swelling
pain
Rapidly generated after tissue injury and play a pivital role in the development and maintenance of these inflammatory processes
kinins
Kinin B1 receptors
located in aorta and mesenteric veins
Kinin B2 receptors
located in the jugular vein and carotid arteries
g-protein coupled
more widespread than B1
analogues of des Arg9-bradykinin or des Arg10-kallidine are selective antagonists for
kinin B1 receptor
analogues of (dephen7) bradykinin are antagonists for
kinin B2 receptor
widely used in animal studies but inactive on human B2 receptors
Icatibant
2nd gen B2 receptor antagonist
orally effective potent and selective for b2 in humans
treatment of hereditary angioedema and pain
t 1/2 60 min
Fr173657 and NPC18884
3rd generation kinin B2 antagonist
orally active
treatment of inflammatory pain in humans
t1/2 = 90 min
Activation of B2 kinin receptors in all tissues leads to
stimulation of PI-PLC resulting in formation of inositol phosphates and DAG => increase Ca2+ levels
Bradykinin induced increases in Ca2+ of human airway smooth muscle are mediated both by
activation of PI-PLC
calcium influx via receptor operated calcium channels
Author
Rx2013
ID
80025
Card Set
Pharmacology Exam 6
Description
Serotonin & kinins
Updated
2011-04-16T20:01:34Z
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