Lecture 10 Histamine & 5-HT

Question 1

The four histamine receptors are what kind of receptor

Answer 1

G-Protein Receptors

Question 2

H1 Receptors are important in

Answer 2

Allergy and Inflammation

Question 3

H2 Receptors are important in

Answer 3

Gastric Acid Secretion

Question 4

Histamine Agonist Effects

Answer 4

Bronchi Constrictor
Vasodilator and Increases Permeability
Increases Heart Rate
Stimulates Gastric Acid Secretion

Local Vasodilation = (Wheal and Flare)

Question 5

Antihistamines effect which receptors

Answer 5

H1 Receptors

Question 6

Peptic Ulcer Drugs effect which receptors

Answer 6

H2 Receptors

Question 7

Antihistamines are what kind of agonist

Answer 7

Inverse Agonist

They block receptors and further decrease their activity

Question 8

Do unliganded histamine receptors have any activity?

Answer 8

Yes they have some basal activity even when not bounded

Question 9

Diphenhydramine

Answer 9

First Generation Antihistamine

Blocks H1
Enters CNS easily –> Sedation
Also blocks autonomic transmitters
Adrenergic
Cholinergic
Serotonergic

Question 10

Hydroxyzine

Answer 10

First Generation Antihistamine

Blocks H1
Enters CNS easily –> Sedation
Also blocks autonomic transmitters
Adrenergic
Cholinergic
Serotonergic

Question 11

Cetrizine

Answer 11

Second/Third Generation Antihistamine

Specific for H1 Receptors
p-glycoprotein substrate

Question 12

Loratidine

Answer 12

Second/Third Generation Antihistamine

Specific for H1 Receptors
p-glycoprotein substrate

Question 13

Fexofenadine

Answer 13

Second/Third Generation Antihistamine

Specific for H1 Receptors
p-glycoprotein substrate

Question 14

Levoceterizine

Answer 14

Second/Third Generation Antihistamine

Specific for H1 Receptors
p-glycoprotein substrate

Question 15

Desloratadine

Answer 15

Second/Third Generation Antihistamine

Specific for H1 Receptors
p-glycoprotein substrate

Question 16

5-HT (1-7) are what kind of receptors

Answer 16

All are G-Proteins

Exception 5-HT3 is a ligand-gated cation channel

Question 17

5-HT(1B) Main Function

Answer 17

Pulmonary Vasoconstriction (Lungs)
Presynaptic Inhibition (CNS)

Question 18

5-HT(1D) Main Function

Answer 18

Cerebral Vasoconstriction (Brain)
Locomotion (CNS)

Question 19

5-HT(2A)

Answer 19

Platelet Aggregation
Neuronal Excitation (CNS)
Smooth Muscle Contraction

Question 20

5-HT(3)

Answer 20

Neuronal Excitation (Autonomic)
Emesis (Vomit)
Anxiety (CNS)

Question 21

Sumatriptan

Answer 21

5-HT(1B/1D/1F) Receptor Agonist
Acute
Constricts Cerebral Arteries (Decrease Blood Flow)
Inhibits Trigeminal Nerve Transmission

Question 22

Almotriptan

Answer 22

5-HT(1B/1D/1F) Receptor Agonist
Acute

Constricts Cerebral Arteries (Decrease Blood Flow)
Inhibits Trigeminal Nerve Transmission

Question 23

Pizotifen

Answer 23

5-HT(2) Receptor Antagonist
Preventative

Prevents Constriction of Cerebral Arteries

Question 24

Cyproheptidine

Answer 24

5-HT(2) Receptor Antagonist
Preventative

Prevents Constriction of Cerebral Arteries
Treats Carcinoid Effects

Question 25

5-HT and Carcinoid Effect

Answer 25

Flushing
Diarrhea
Bronchoconstriction
Hypotension
Fibrotic Stenosis of Heart valves (Inflammation)

Question 26

Physiological Effects of 5-HT

Answer 26

Large Vessels Constrict
Small Vessels Dilate

Contracts bronchi and uterus smooth muscles

Increases GI motility

Stimulate Platelet Aggregation

Stimulate peripheral nociceptive nerve endings

Excites/Inhibits CNS