USMLE STEP 1 Pharmacology
What are the major functions of the α1 receptor?(Ans- 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?(Ans- Decrease sympathetic outflow, decrease insulin release, decrease lipolysis, increase platelet aggregation, decrease aqueous humor production
What are the major functions of the β1 receptor?(Ans- Increase heart rate, increase contractility, increase renin release, increase lipolysis
What are the major functions of the β2 receptor?(Ans- 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?(Ans- CNS, enteric nervous system
What are the major functions of the M2 receptor?(Ans- Decrease heart rate and contractility of atria
What are the major functions of the M3 receptor?(Ans- 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)
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What are the major functions of the D1 receptor?(Ans- Relaxes renal vascular smooth muscle
What are the major functions of the D2 receptor?(Ans- Modulates transmitter release, especially in the brain
What are the major functions of the H1 receptor?(Ans- Increase nasal and bronchial mucus production, increase vascular permeability, contraction of bronchioles, pruritis, pain
What are the major functions of the H2 receptor?(Ans- Increase gastric acid secretion
What are the major functions of the V1 receptor?(Ans- Increase vascular smooth muscle contraction
What are the major functions of the V2 receptor?(Ans- Increase H2O permeability and reabsorption in collecting tubules of kidney (V2 is found in the "2" kidneys)
What receptors are associate with Gq?(Ans- H1, α1, V1, M1, and M3
What receptors are associated with Gs?(Ans- H2, B1, B2, V2, D1
What receptors are associated with Gi?(Ans- M2, α2, D2
Bethanechol (Ans- -Direct cholinergic agonist -Activates bowel and bladder smooth muscle -Used in postoperative and neurogenic ileus -Resistant to AChE 2 / 4
Carbachol (Ans- -Direct cholinergic agonist -Carbon copy of acetylcholine -Constricts pupils and relieves intraocular pressure in glaucoma
Methacholine (Ans- -Direct cholinergic agonist -Stimulates muscarinic receptors in airways when inhaled -Used as a challenge test for diagnosis of asthma
Pilocarpine (Ans- -Direct cholinergic agonist -Contracts ciliary muscle of eye (open angle glaucoma), contracts pupillary sphincter (closed angle glaucoma) -Potent stimulator of sweat, tears and saliva -AChE resistant
Donepezil (Ans- -Anticholinesterse - increases ACh -Alzheimer disease
Galantamine (Ans- -Anticholinesterse - increases ACh -Alzheimer disease
Rivastigmine (Ans- -Anticholinesterse - increases ACh -Alzheimer disease 3 / 4
Edrophonium (Ans- -Anticholinesterse - increases ACh -Historically used to diagnose myasthenia gravis (MG is now diagnosed by anti-AChR Ab test.
Neostigmine (Ans- -Anticholinesterse - increases ACh -Used in postoperative and neurogenic ileus and urinary retention, myasthenia gravis, and postoperative reversal of neuromuscular junction blockade
Physostigmine (Ans- -Anticholinesterse - increases ACh -Used in anticholinergic toxicity -Crosses the blood-brain barrier (CNS)
Pyridostigmine (Ans- -Anticholinesterse - increases ACh -Increases muscle strength -Used in myasthenia gravis (long acting) -Does not penetrate CNS
Atropine (Ans- -Muscarinic antagonist -Used in bradycardia and for ophthalmic applications -Also used as antidote for cholinesterase inhibitor poisoning -Actions include increase pupil dilation, cycloplegia, decreased airway secretions, decreased acid secretions, decreased gut motility, decreased bladder urgency in cystitis
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