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Flashcards in Histamine Agonists Deck (21):
1

How are histamine agonists formed

Decarboxylation of L-histidine

2

What kind of receptors do they bind

G protein

3

G protein for H1

Gq

4

G protein for H2

Gs

5

Most prominent effect of histamine agonists

Vasodilation (H1 and H2)

6

Where is H1 located

Endothelium, SM, nerve endings

7

Where is H2 located

Gastric mucosa, Cardiac muscle cells, immune cells

8

What is the action of H3

Reduce NT release from histaminergic and other neurons

9

What is the action of H4

Chemotactic for EOS and mast
On WBCs in BM and blood
Inflammation and allergies

10

Is the histamine receptor constitutive

Yes

11

What is the histamine triple response

Localized red spot
Flare
Wheal

12

What mediates GIT contraction and bronchconstriction

H1

13

CVS action of H2

Increase contractility and HR

14

CVS action of H1

Increase capillary permeability
Edema
Urticaria

15

What H receptor stimulates nerve endings causing pain and itching

H1

16

Which receptor mediates gastric acid secretion

H2

17

Clinical use of histamine

Pulmonary function testing

18

Histamine Contraindications

Asthmatics
Peptic ulcer disease/GI bleed

19

Main AE of histamine

Anaphylaxis

20

Immunological method of histamine release

Ag → IgE (on mast) → degranulation and release
Ca mediated

21

Chem/Mech method of histamine release

Morphine/Tubocurarine (amines) displace histamine from heparin complex