Anti-Histamine Drugs

What are the peripheral and central effects of histamine and serotonin

Major effects on smooth muscle

Some antihistamines that cross BBB act as

Sedatives

How is histamine produced

Decarboxylation of amino acid histidine by a histidine decarboxylase

True or false:

Histamine stimulates gastric acid secretion

True

Functions of histamine

• IgE mediated allergic reactions

• Regulate gastric acid secretion

• Vasodilator

Histamine binds to how many receptors

4

What is ECl cells

Cells in stomach that synthesize and store histamine and once released it binds to histamine receptors in parietal cells

H1 and H2 receptors mediate what functions

Peripheral functioms

Where is H3 and H4 located

H3: brain

H4: immune, mast cells

What is the mechanism or H receptor related to excessive acid secretion

H2 receptor activation

Histamine is normally bound to ______ and displaced by morphine

Heparin

Which receptor is coupled to phospholipase C

H1

What are the responses of H1

• vasodilation

• Bronchoconstriction

• Endothelial cell contraction

• Permeability

• Pain and itching nerve stimulation

The expression of H1 includes:

• smooth muscle cells of airways, GI tract, CV system, endothelial cells, and lymphocytes and brain (post synaptic)

What is the difference between stimulation and meditation

What is the effect in endothelial cells

Vasodilation (not directly)

Effect on smooth muscle

Vasoconstriction

Which receptor is coupled to Gs to Adenylyl Cyclase

H2

Where is H2 expressed