GCPR (alpha, beta, muscarinic, dopamine, histamine, vasopressin)

Question 1

Alpha 1
Agonist: phenylephrine, NE
Antagonist: Doxazosin, tamsulosin

Answer 1

Increases:

• vasoconstriction
• pupil dilation
• intestinal & bladder sphincter muscle contraction

Question 2

Alpha2
Agonist: methyldopa
Antagonist: Mirtazapine

Answer 2

Decreases:
- sympathetic outflow
- insulin release
- lipolysis
Increases:
- platelet aggregation

Question 3

Beta1
Agonist: dobutamine
Antagonist: ABEAM (atenolol, metoprolol)

Answer 3

Increases:

• heart rate
• contractility
• renin release
• lipolysis

Question 4

Beta2
Agonist: albuterol, salmeterol
Antagonist: non-selective beta blockers

Answer 4

Increases:
- vasodilation
- bronchodilation
- HR
- contractility
- lipolysis
- insulin release
- aqueous humor production 
- ciliary muscle relaxation (accommodation)
Decreases:
- uterine tone (tocolysis)

Question 5

M1 (PS, muscarinic)
Agonist: bethanechol
Antagonist: benztropine, scopalamine

Answer 5

CNS, enteric nervous system

Question 6

M2 (PS, muscarinic)
Agonist:
Antagonist: Atropine

Answer 6

Decreases:

• HR
• contractility of atria

Question 7

M3 (PS, muscarinic) - no pure M3 drugs
Agonist: Carbachol, pilocarpine, methacholine
Antagonist:
- Eyes: Atropine, hematropine, tropicamide
- Resp: Ipratropium, tiotropium,
- GU: Oxybutynin, darifenacin, solifenacin
- GI/resp: Glycopyrrolate

Answer 7

Increases:

• exocrine gland secretion (lacrimal, salivary, gastric acid)
• gut peristalsis
• bladder contraction
• bronchoconstriction
• pupillary sphincter muscle contraction (miosis)
• ciliary muscle contraction

Question 8

D1
Agonist: dopamine (D1 = D2), fenolopam (selective)
Antagonist: not on purpose

Answer 8

Relaxes renal vascular smooth muscle (increases renal perfusion)

Question 9

D2
Agonist: dopamine, bromocriptine, cabergoline
Antagonist: metoclopromide, antipsychotics

Answer 9

Modulates transmitter release, especially in the brain

Question 10

H1
Agonist: none
Antagonist: diphenhydramine, loratadine

Answer 10

Increases:

• nasal and bronchial mucus production
• vascular permeability
• bronchoconstriction
• pruritis
• pain

Question 11

H2
Agonist: none
Antagonist: cimetidine, ranitidine, famotidine, nizatidine

Answer 11

Increases gastric acid secretion

Question 12

V1

Answer 12

Vasoconstriction

Question 13

V2
Agonist: desmopressin (DDAVP)
Antagonist: maybe demeclocycline

Answer 13

Increases water permeability and reabsorption in the collecting tubules of the kidneys; stimulates release of vWF from endothelial cells

Question 14

Gq pathway

Answer 14

Gq –> phospholipase C –> IP3 –> increased [Ca2+]

Also phospholipase C –> DAG –> Protein Kinase C

Question 15

Gs pathway

Answer 15

Gs –> adenylate cyclase –> cAMP –> PKA –> increased [Ca2+] in heart and decreased myosin light chain kinase (results in smooth muscle dilation)

Question 16

Gi pathway

Answer 16

Gi inhibits adenylate cyclase –> decreased cAMP –> decreased PKA —> decreased [Ca2+] in heart and increased myosin light chain kinase (smooth muscle contraction)