autonomics

Question 1

Sympathetic receptors

• alpha1
• alpha2
• Beta1
• beta2

Answer 1

• GPCR
• alpha1= vasoconstriction, mydriasis, intest and bladder sphincter mm contraction
• alpha2= autoreceptor (negative feedback – decrease sympa outflow)
• beta1= increase HR and contractility, renin release
• beta2= bronchodilation, vasodilation

Question 2

Parasympathetic receptors + DA, HA and ADH

Answer 2

• M1= CNS, enteric NS
• M2= decrease HR and contractility
• M3= bladder contraction, exo gland secretions, peristalsis, bronchoconstriction, miosis and accomodation
• D1 = relax renal vasculature
• D2= mediates NTM release in brain
• H1= allx symptoms
• H2= gastric acid secretion
• V1= vasoconstriction
• V2= kidney action

Question 3

GPCR pathways

Answer 3

1. Gq –> PIP2 (lipids) –> IP3 (Ca release) and DAG –> PKC
2. Gs –> AC –> cAMP –> PKA
3. Gi inhibits AC –> etc

QC’s HAVe 1 M+M: Gq - H1, alpha1, V1, M1 and M3

MAD 2’s for Gi: M2, alpha2, D2

rest = Gs

Question 4

direct cholinomimetics

Answer 4

• “chol”
• Bethanechol- post-op ileus, urinary retention (B for Bladder and bowel)
• Carbachol- glaucoma
• Methacholine- asthma challenge
• Pilocarpine- glaucoma

Question 5

indirect cholinomimetics

Answer 5

• AChE inhibitors
• neostigmine- postop and neurogenic ileus
• pyridostigmine- MS (long-acting)
• physostigmine- fixes atropine OD
• Donepezil, rivastigmine- Alzheimer’s
• Edrophonium- dx MS (short-acting)

Question 6

muscarinic antags

Answer 6

• “trop”
• Atropine, homatropine, tropicamide- used by eye dr
• Benztropine- Parkinson
• Scopalamine- Motion sickness
• Ipratropium, Tiotropium- COPD, asthma
• Oxybutynin, Darifenacin- reduce GU urgency

Question 7

direct sympathomimetics

Answer 7

• Epi: B>a (alpha predominates at high doses) –anaphylaxis
• NE: a1>a2>B1 – hypotension (ie: septic shock)
• Isoproterenol: B1=B2
• DA: D1=D2 – shock
• Dobutamine: B1 – cardiogenic shock (acute HF)
• phenylephrine: a1>a2 – rhinitis (vasoconstriction –> decongestion)
• albuterol, salmeterol, terbutaline: B2 – asthma,COPD
• clonidine: a2– use in HTN emergency
• a-methyl dopa: a2 – HTN in pregnancy

Question 8

indirect sympathomimetics

Answer 8

• amphetamine: release stored catecholamines – narcolepsy, ADD, obesity
• ephedrine: release stores cats – nasal decongestion
• cocaine: reuptake inhibitor – local anesthetic

Question 9

alpha antag

Answer 9

• phenoxybenzamine– pheo (irreversible)
• phentolamine – pheo (reversible)
• prazosin, terazosin – a1 selective (HTN in BPH)
• mirtazapine – a2 selective (depression to help sleep, gain weight)

Question 10

beta blockers

Answer 10

• A-M are B1 selective (1st half of alphabet)
• N-Z have B2 actions
• carvedilol and labetalol have some alpha blockade
• uses: angina, MI (metoprolol or carvedilol), SVT, HTN, CHF, glaucoma
• toxicity: impotency, can mask hypoglycemia in diabetics, asthma
• CI: acute HF, bradycardia, AV block, cocaine users