USMLE STEP 1 PHARMACOLOGY EXAM 2025 | QUESTIONS
WITH ACCURATE SOLUTIONS
What are the major functions of the α1 receptor? - Precise
Answer ✔✔Increase vascular smooth muscle contraction,
increase pupillary dilator muscle contraction (mydriasis),
increase intestinal and bladder sphincter muscle
contraction
What are the major functions of the α2 receptor? - Precise
Answer ✔✔Decrease sympathetic outflow, decrease
insulin release, decrease lipolysis, increase platelet
aggregation, decrease aqueous humor production
What are the major functions of the β1 receptor? - Precise
Answer ✔✔Increase heart rate, increase contractility,
increase renin release, increase lipolysis
What are the major functions of the β2 receptor? - Precise
Answer ✔✔Vasodilation, bronchodilation, increase
lipolysis, increase insulin release, decrease uterine tone
,(tocolysis), ciliary muscle relaxation, increase aqueous
humor production
What are the major functions of the M1 receptor? -
Precise Answer ✔✔CNS, enteric nervous system
What are the major functions of the M2 receptor? -
Precise Answer ✔✔Decrease heart rate and contractility
of atria
What are the major functions of the M3 receptor? -
Precise Answer ✔✔Increase exocrine gland secretions
(e.g., lacrimal, salivary, gastric acid), increase gut
peristalsis, increase bladder contraction, increase
bronchoconstriction, pupillary sphincter muscle
contraction (miosis), ciliary muscle contraction
(accommodation)
What are the major functions of the D1 receptor? - Precise
Answer ✔✔Relaxes renal vascular smooth muscle
,What are the major functions of the D2 receptor? - Precise
Answer ✔✔Modulates transmitter release, especially in
the brain
What are the major functions of the H1 receptor? - Precise
Answer ✔✔Increase nasal and bronchial mucus
production, increase vascular permeability, contraction of
bronchioles, pruritis, pain
What are the major functions of the H2 receptor? - Precise
Answer ✔✔Increase gastric acid secretion
What are the major functions of the V1 receptor? - Precise
Answer ✔✔Increase vascular smooth muscle contraction
What are the major functions of the V2 receptor? - Precise
Answer ✔✔Increase H2O permeability and reabsorption
in collecting tubules of kidney (V2 is found in the "2"
kidneys)
, What receptors are associate with Gq? - Precise Answer
✔✔H1, α1, V1, M1, and M3
What receptors are associated with Gs? - Precise Answer
✔✔H2, B1, B2, V2, D1
What receptors are associated with Gi? - Precise Answer
✔✔M2, α2, D2
Bethanechol - Precise Answer ✔✔-Direct cholinergic
agonist
-Activates bowel and bladder smooth muscle
-Used in postoperative and neurogenic ileus
-Resistant to AChE
Carbachol - Precise Answer ✔✔-Direct cholinergic
agonist
-Carbon copy of acetylcholine
WITH ACCURATE SOLUTIONS
What are the major functions of the α1 receptor? - Precise
Answer ✔✔Increase vascular smooth muscle contraction,
increase pupillary dilator muscle contraction (mydriasis),
increase intestinal and bladder sphincter muscle
contraction
What are the major functions of the α2 receptor? - Precise
Answer ✔✔Decrease sympathetic outflow, decrease
insulin release, decrease lipolysis, increase platelet
aggregation, decrease aqueous humor production
What are the major functions of the β1 receptor? - Precise
Answer ✔✔Increase heart rate, increase contractility,
increase renin release, increase lipolysis
What are the major functions of the β2 receptor? - Precise
Answer ✔✔Vasodilation, bronchodilation, increase
lipolysis, increase insulin release, decrease uterine tone
,(tocolysis), ciliary muscle relaxation, increase aqueous
humor production
What are the major functions of the M1 receptor? -
Precise Answer ✔✔CNS, enteric nervous system
What are the major functions of the M2 receptor? -
Precise Answer ✔✔Decrease heart rate and contractility
of atria
What are the major functions of the M3 receptor? -
Precise Answer ✔✔Increase exocrine gland secretions
(e.g., lacrimal, salivary, gastric acid), increase gut
peristalsis, increase bladder contraction, increase
bronchoconstriction, pupillary sphincter muscle
contraction (miosis), ciliary muscle contraction
(accommodation)
What are the major functions of the D1 receptor? - Precise
Answer ✔✔Relaxes renal vascular smooth muscle
,What are the major functions of the D2 receptor? - Precise
Answer ✔✔Modulates transmitter release, especially in
the brain
What are the major functions of the H1 receptor? - Precise
Answer ✔✔Increase nasal and bronchial mucus
production, increase vascular permeability, contraction of
bronchioles, pruritis, pain
What are the major functions of the H2 receptor? - Precise
Answer ✔✔Increase gastric acid secretion
What are the major functions of the V1 receptor? - Precise
Answer ✔✔Increase vascular smooth muscle contraction
What are the major functions of the V2 receptor? - Precise
Answer ✔✔Increase H2O permeability and reabsorption
in collecting tubules of kidney (V2 is found in the "2"
kidneys)
, What receptors are associate with Gq? - Precise Answer
✔✔H1, α1, V1, M1, and M3
What receptors are associated with Gs? - Precise Answer
✔✔H2, B1, B2, V2, D1
What receptors are associated with Gi? - Precise Answer
✔✔M2, α2, D2
Bethanechol - Precise Answer ✔✔-Direct cholinergic
agonist
-Activates bowel and bladder smooth muscle
-Used in postoperative and neurogenic ileus
-Resistant to AChE
Carbachol - Precise Answer ✔✔-Direct cholinergic
agonist
-Carbon copy of acetylcholine
