Autacoids - Histamine Flashcards
Most important amine autacoids
Histamine & serotonin
Ergot alkaloids have effects on _____ and _____
Serotonin receptors, smooth muscles
Ergot alkaloids act on which organs.
CNS, pituitary, uterus, blood vessels
Histamine is stored in which cell types?
Mast cells, enterochromaffin cells, gut, neurons
How can histamine be detected in the body?
Level of Imidazole acetic acid in the urine
Pathophysiologic role of Histamine
Seasonal rhinitis (hay fever), Urticaria, Angioneurotic edema, control of stomach acid secretion
Modulates smooth muscle contraction, neurotransmitters and for vasodilation
H1
Give H1 and H2’s signal transduction unit.
Gq/G11, Gq/G11, Gs (respectively)
These histamine receptors act on Gi/Go subunits.
H3, H4
All Histamine receptors except _____ can be found at the brain.
H4
Give locations of each Histamine receptor.
H1: Heart, brain, mast cells
H2: Heart, brain, neutrophil, parietal cell
H3: Brain, PNS
H4: Blood cells (mast, eosino, monocyte)
Give the physiological function of each Histamine receptor.
H1: smooth ms contraction, modulates neurotransmitters, vasodilate
H2: (+) gastric acid, leukocyte function
H3: CNS activity
H4: allergic reaction
This H1 receptor antagonist has strong sedative effects and can pass BBB.
1st generation agents
Give the characteristics of Second generation H1 receptor antagonists.
Metabolized by CYP3A4, less lipid soluble, less sedative (less CNS distribution)
H1 receptor antagonists reach peak blood concentration in ___ hours and has a duration of action of ___ hours.
1-2, 4-6
Which H1 receptor antagonist drug acts as an exception by having a longer duration of action?
Meclizine (Bonamine) (12-24 hours)
H1 antagonist: ______ moiety; H2 antagonist: _________ ring
ethylamine, imidazole
H1 receptor pharmacodynamics: _____ antagonism; mast cell stabilization at ____ doses
reversible competitive, low