Histamine, Serotonin Flashcards
Test 3
Describe autocoid transmission
local release and action of mediators like histamine, serotonin, prostaglandins, and leukotrienes
Describe Neuropathic vs psychogenic pruitis
Neuropathic: autacoid group binding to receptor
Psychogenic: thinking about itching makes you itch
Histamine is ________ stored & inactivated
rapidly
What do histamine receptors in the stomach produce?
Hydrochloric acid
What drugs induce histamine release?
Morphine
Tubocurarine
_____ can induce histamine release
trauma
Where are H1, H2, H3 receptors
H1 - blood vessels
H2 - stomach
H3 - brain
List the major organ system effects of histamine and serotonin.
Histamine: CVS: vasodilation & increased permeability
Respiratory: bronchoconstriction
GI: stimulating gastric acid secretion
Serotonin: CNS: regulating mood, sleep, and appetite
CVS: vasoconstriction/dilation
GI: promoting peristalsis
List the effects seen in the Triple Response of allergy testing and mediators.
** injecting small amounts of allergens to see what has a positive reaction**
Redness (due to capillary dilation)
Flare (a wider area of redness due to arteriolar dilation)
Wheal (a raised area due to increased vascular permeability) Mediators involved include histamine and other inflammatory substances
Itch
These are mediated by the release of histamine and other inflammatory mediators from mast cells.
List H1 antagonist
1st generation: Benadryl, phenergan, dramamine (crosses BBB - sedative effects - can be used for nausea)
2nd: Claritin, allegra, zyrtec (no CNS effects)
What drug counters histamine but not on the H-Receptors?
Epi
List H2 antagonists
OTC antacids
-dine
Children may have _______ effects with H1 antagonist
reverse
T/F: Platelet degranulation releases serotonin
T
Where is most of our serotonin stored?
90% stored in enterochromaffin cells in the gut
Describe the pharmacology of the 2 groups of H1 antihistamines and list prototypical agents for each group
a. First generation (sedating): Cross blood-brain barrier, have anticholinergic effects.
i. Prototypes include diphenhydramine (Benadryl) and chlorpheniramine.
b. Second generation (non-sedating): Do not cross blood-brain barrier as readily, fewer anticholinergic effects.
i. Prototypes include cetirizine (Zyrtec) and loratadine (Claritin).