List the effects of:

1)H1

2) H2

• 1)
  
  • Mucus secretion
  • Vascular relaxation
  • Bronchial Constriction
  • Itching

Agonist = 2-methylhistamine

Antagonist = Classic Antihisatmine Agents

-----------------------------------
2)

H1 blockers

 ag/antag

H2 blockers

  ag/antag

H3 agonists

• Diphendydramine (benidril)
• Chlorpheniramine
• Fexofenadine
• Ioratadine
• ==========================
• Cimetidine
• ranitidine
• famotidine
• nizatidine

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• resp for the central effect of histamine
• Agonist -  Alpha methlhistamine

T/F  Bact in food releases Histamine that is uptaken into the body, causing swelling.

2) List the areas of conc. Histamine in body:

FALSE

All histomine in body is METABOLIZED and excreted in urine

The reason none is taken up effectively is becase any absorbed by intestines is immediately broken down in liver.

 ___________________________

2) Lung, mucus memb, skin, stomach, duodenum

1. How is histamine stored?s

1. in secretory granules bound to heparin     (sotred in mast cells/basophils)        
2. 
   

how is histamine released from basophils/mast cells?

Inhibits relase?

Previous exposure -- > specification of IgE

second exposure:

cross-link of IgE bound to Fc

=> phospholipase C activation

=> Ca+ relaser from ER ====>HISTAMINE RELEASE

adenylyl cyclase/cAMP inhibits Histamine release

epinephrine

Anaphylactic = ana (against) + Phylaxis (Protection)

Red spot: (vasod)

Flare: (RBC)

Wheal: (edema)

effective antimotion sickness drug

cromolyn sodium

omalizumab

physostigmine

inhibits ACHcholinesterase

***CAN PENETRATE BBB***

neostigmine cannot

VESTIBULAR

+Vomiting = Cholinergic

H1 blocker inhibits (dramamine) Cholinergic stim

-Vominting = Sympathetic

 Alpha Adrenergic increases Sympathetic Effect

(Sudafed)

How do thse drugs affect vomiting?

1) Sudafed

2) Dramamine

1) Stimulates the Alpha Adrenergic system (Sympathetic), which is a supressor of the vomit reflec from the RETICULAR system

2) Inhibits the CHOLINERGIC system, which is a positive stimulator

Astemizole is a second generation H1 blocker --

when is it CONTRAINDICATED?

causes Arrhythmias when taken in conj with Ketoconazole or eythromycxin

blocks Histamine release from mast cells

prophylactic treatment of Asthma

blocks Histamine release from mast cells

Blocks monoclonal antibody that binds to Fc domain on IgE

blocks ability of Fc to bind to Mast Cell

Cimetidine

ranitidine

famotidine

nizatidine

Block Gastric HCL secretion

Cimetidine

side effects

newer drugs

H2 blocker

given to allow gastric ulcer to heal

inhibits helatic Cytochrome p450

==> drug interactions

------

Famotidine doesnt bind p450

C>R>N>F

anticholineric properties,

**the cholinergic system is a promotor of the vomit reflex -- the Alpha adrenergic is a negative**

is similar to atropine poison in CHINLDREN

less effect on adults

1)  What i s the result of a blockade of H2 receptors?

2)  Name a definative side effect of H2

3)  H1?

Decrease in cAMP

G(s) = protein coupled receptors, like Beta adrenoreceptors

 =======================

2)   P450 enzyme inhibition

----------------

3) Anyi-motion sickness

*** list the H1 blockers ***

2-Methylhistamine

PLC

• Mucus, 
• bronchoconstrict
• vasod
• itch

D
C
F
L
D
C

Diphenydramine

Chlorpheniramine

Fexofenadine

Loratadine

Desloratadine

Cetirizine

***List the H2 Blockers***

4-Methylehistamine

Adenylyl Cyclase

Dec Gastric HCL

C
R
F
N

Cimetidine

ranitidine

famotidine

nizatidine

list the two methods of secreting HCL

*and one method of inhibiting *

1) H2 receptors - Adenylyl Cyclase -> Inc cAMP -> stimulaes production of HCL

2) Acetylcholine and Gastrin

increse Castimulate HCL in Parietal cells

*Prostoglandin inhibits Adenylyl Cyclase*