USMLE STEP 1 Pharmacology Test Bank (Questions and Answers)

What are the major functions of the α1 receptor? - 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? - Decrease sympathetic outflow, decrease insulin release, decrease lipolysis, increase platelet aggregation, decrease aqueous humor production What are the major functions of the β1 receptor? - Increase heart rate, increase contractility, increase renin release, increase lipolysis What are the major functions of the β2 receptor? - 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? - CNS, enteric nervous system What are the major functions of the M2 receptor? - Decrease heart rate and contractility of atria What are the major functions of the M3 receptor? - 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? - Relaxes renal vascular smooth muscle What are the major functions of the D2 receptor? - Modulates transmitter release, especially in the brainWhat are the major functions of the H1 receptor? - Increase nasal and bronchial mucus production, increase vascular permeability, contraction of bronchioles, pruritis, pain What are the major functions of the H2 receptor? - Increase gastric acid secretion What are the major functions of the V1 receptor? - Increase vascular smooth muscle contraction What are the major functions of the V2 receptor? - Increase H2O permeability and reabsorption in collecting tubules of kidney (V2 is found in the "2" kidneys) What receptors are associate with Gq? - H1, α1, V1, M1, and M3 What receptors are associated with Gs? - H2, B1, B2, V2, D1 What receptors are associated with Gi? - M2, α2, D2 Bethanechol - -Direct cholinergic agonist -Activates bowel and bladder smooth muscle -Used in postoperative and neurogenic ileus -Resistant to AChE Carbachol - -Direct cholinergic agonist -Carbon copy of acetylcholine -Constricts pupils and relieves intraocular pressure in glaucoma Methacholine - -Direct cholinergic agonist -Stimulates muscarinic receptors in airways when inhaled