Autacoids: Histamine, Bradykinin, NO Flashcards
Histidine to Histamine uses what rxn and cofactor
decarboxylation and vitamin B6
histamines are found in what major sites: (3)
mast cell granules
brain
ECL cells of stomach
stimulation of H1 receptors (Gq) causes what 2 things:
- bronchial and GI smooth m. contraction
- edema
stimulation of H2 receptors (Gs) causes what to happen
increased acid secretion in GI tract
what 2 downstream signaling molecules promote exocytosis
cAMP
Ca2+
2 main inhibitors of mast cell degranulation
Cromolyn sodium
Nedocromil
the 2 antihistamines that penetrate BBB and reach TMN (where histamine is produced)—-causing drowsiness
Diphenhydramine
Dimenhydrinate
1st generation antihistamines (diphenhydramine and dimenhydrinate) vs. 2nd generation anti-histamines (cetirizine)
2nd generation do not cross BBB and does not cause drowsiness
type of histamine that blocks its own release; self-inhibitory autoreceptor
H3 (Gi)
histamine antagonists that can be used to tx Alzheimer’s (increases cognitive enhancement)
H3 antagonist
sx’s include urticaria pigmentosa; in children
cutaneous mastocytosis
sx’s include flushing, N/V/D, tachycardia, hypotension, syncope; in adults
systemic mastocytosis
treatment of mastocytosis
Antihistamines of H1 and H2
mepyramine
cetirizine
antihistamines (H1 antagonists)
cimetidine, ranitidine
antihistamines (H2 antagonists)
what degrades bradykinin
ACE kinase
what leads to increase in bradykinin and a dry cough commonly seen when treating HTN with this medicine
ACE inhibitor
actions of bradykinin and kallidin resemble what
histamine
bradykinin and kallidin lead to what
vasodilation
what is the problem of bradykinin and kallidin
causes angioedema
Ach binds to M3 and what is released in endothelial vascular smooth m cell that causes relaxation
NO (nitric oxide)
increase in intracellular Ca2+ leads to what activation
MLCK
activation of MLCK leads to what
MLC phosphorylation then contraction
when cAMP is increased and so is PKA, what happens
MLCK is phosphorylated and contraction doesn’t happen
NO increases cGMP which leads to phosphorylated MLC inhibiting what
contraction
