Term
|
Definition
| decarboxylation of AA L-histadine via pyridoxal phosphate dependent enzyme and L-histadine decarboxylase |
|
|
Term
| degradation of histamines |
|
Definition
rapidly converted to inactive metabolite
Periphery: oxidative deamination: catalized by diamine oxidase making imidazole acetic acid
CNS and periphery: methylation of tele-nitrogen in imidazole ring catalized by histamine-N-methyltransferase making t-N-methylhistamine |
|
|
Term
| 3 sites of histamine storage |
|
Definition
found in almost all tissies: low in plasma and body fluids
mast cells: major site of storage and release, activated by IgE
basophils: similar to mase cells, high IgE binding affinity, store and secrete histamine |
|
|
Term
| mast cells: locations 3, how is histamine stored |
|
Definition
high in skin, mucosa of bronchial tree and intestinal mucosa
histamine stored as granules with proteoglycan and chondroitin sulfate E |
|
|
Term
| basophils: location of high concentration, how does is histamine stored |
|
Definition
high in neurons of CNS
histamine stored in granules with proteogltcan chondroitin monosulfate |
|
|
Term
| 3 causes of histamine release |
|
Definition
| allergic disorders, drugs, endogenous peptides (bradykinin, substance P) |
|
|
Term
| explain the 2 processes of histamine release |
|
Definition
cytolytic: plasma membrane is damaged and contents leak out
non-cytolytic: ligand binds receptor on mast cell, ATP dependent change in Ca causes leaking of cytoplasm and exocytosis of granules |
|
|
Term
| what are the MOA of the 3 types of histamine receptors |
|
Definition
H1, H2, H3: G protein coupled receptors
H1: Gi receptor coupled to phospholipase C forms IP3 which releases Ca from ER and DAG which activates Ca via calmodulin dependent protein kinase and phospholipase A2 in target cell |
|
|
Term
| functions of the H1 and H2 receptors 3 |
|
Definition
1. histamine stimulates pain and hitch in nerve endings
2. histamine shock: large dose decreases BP and small vessels trap blood decreasing BV and CO
3. endothelium: increases Ca > phospholipase A2 > NO > diffusion to smooth muscle > guanylyl cyclase >>
> H1 receptor cGMP activates protein kinase and causes fast capillary dilation, increased permeability, lymph flow, and edema
> H2 receptor cAMP activates protein kinase and causes slow sustained capillary dilation |
|
|
Term
| functions of only the H1 receptr |
|
Definition
|
|
Term
| Tx of autocoid bronchoconstriction |
|
Definition
|
|
Term
| MOA and distribution of 1st gen antihistamine |
|
Definition
competitive reversible H1 inhibitor
crosses BBB
anticholinergic |
|
|
Term
| interactions of 1st gen antihistamine 3 |
|
Definition
| EtOH, CNS depressants, MAOI |
|
|
Term
| effects of only 1st gen antihistamine 8 |
|
Definition
CNS: restless, nervous, insomnia
OD: excitation, convulsion, coma, respiratory collapse
anticholinergic: increased SANS, inhibit M receptor / ACh, atropine like |
|
|
Term
| MOA and distribution of 2nd gen antihistamine |
|
Definition
competitive reversible H1 inhibitor
does not cross BBB
no anticholinergic effects |
|
|
Term
| effects of both 1st and 2nd gen antihistamine 7 |
|
Definition
| inhibit histamine on smooth muscle, vasoconstriction, permeability, edema, wheals, flare,itch |
|
|
Term
| what do antihistamines never effect 2 |
|
Definition
anaphylactic bronchoconstriction
H2 vasodilation |
|
|
Term
| what is the story for the 8 1st gen antihisamines |
|
Definition
| dying phrends and dying men hydrated cyclically like pros with purel with chlori and my bro's phrend ramine who used pro meth from a magazine |
|
|
Term
| what are the 8 1st gen antihistamines |
|
Definition
diphenhydramine
dimenhydrinate
hydroxyzine
cyproheptadine
purilamine
chlorpheniramine/brompheniramine
promethazine
meclizine |
|
|
Term
| diphrenhydramine: use 3, SE 2 |
|
Definition
allergies, OTC sleep med, extrapyrmidal SE
SE: sedation, lots of anti-M |
|
|
Term
| dimenhydrinate: use 1, SE 1 |
|
Definition
motion sickness
SE: anti-M |
|
|
Term
| hydroxyzine HCl: use 2, SE 1 |
|
Definition
long acting, skin allergies
SE: CNS depression, lots |
|
|
Term
| cyproheptadine: use 2, SE 3 |
|
Definition
drowsy, increased weight
mild anticholinergic |
|
|
Term
|
Definition
|
|
Term
| chlorpheniramine/brompheniramine: use 1, SE 1 |
|
Definition
allergy
SE: CNS stimulation (daytime med) |
|
|
Term
| promethazine: use 1, SE 2 |
|
Definition
nausea and vomiting
SE: anticholinergic, sleep |
|
|
Term
|
Definition
| motion sickness, less effective |
|
|
Term
| what is the story for 2nd gen antihistamines |
|
Definition
| des and lora dined on citrsy flex or grenadine |
|
|
Term
| what are the 4 2nd gen antihistamines |
|
Definition
desloratadine
loratadine
cetrizine
fexofenadine |
|
|
Term
| SE of the 2 2nd gen antihistamines (1 each) |
|
Definition
desloratadine: renal/hepatic damage (less)
loratadine: renal/hepatic damage
cetrizine: renal/hepatic damage
fexofenadine: renal damage (use 1/3 dose) |
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