Pharmacology -- Autonomic Nervous System Flashcards
Epinephrine
α1, α2, β1, β2
Norepinephrine
α1, α2, β1 (no β2 activity)
GABA
Causes an inhibitory hyperpolarization of cells
Muscarinic receptor
Uses DAG & IP# as second messengers
Parasympathetic control
Bethanechol
Cholinergic
Increases GI & Bladder motility
Tx for atonic bladder post-op
Pilocarpine
Cholinergic
Pupillary constriction=miosis
Ciliary constriction=accomodation
Tx: acute angle glaucoma
Isoflurophate
Organophosphate. Irreversible anti- acetylcholinesterase
Tx glaucoma
Pralidoxime
aka 2 PAM
Reverses organophosphate binding to acetylcholinesterase (thus used in organo. phos poisoning. doesn’t cross BBB so coadmin w atropine)
Neostigmine
Reversible anti-cholinesterase inhibitor
Parasympathomimetic
Tx: Myasthenia gravis
Myasthenia Gravis
Antibodies to the ACh Receptor.
Inc. muscular weakness due to Ach’s week postsynaptic effect @ NMJ. Inactivates receptors
Tubocurarine
Nondepolarizing competitive cholinergic nicotinic ACh receptor antagonist. Prevents Ach binding but does not activate NMJ.
Increases histamine release = dec BP and inc bronchospasm
Tx: skeletal muscle relaxant used w anasthesia (less commonly used currently due to side effects)
Trimethaphan
Nonselectively, competitively binds the nicotinic receptor of both PS and SNS
short acting, IV admin.
Pancuronium
More potent than tubocurium, competitive nicotinic Ach-R antagonist at NMJ, w/o the histamine release
Succinylcholine
Depolarizing noncompetitive cholinergic nicotinic receptor antagonist of muscle action
Opens Na Channels= fasiculations, closes Na channels= paralysis= persistent depol at NMJ
Continuous infusion
alpha1 and eye
Mydriasis (pupil dilation) due to NE. Prozsin blocks (alpha-adrenergic blocker, specific for the alpha-1 receptors.)
Muscarinic receptor and the Eye
Miosis due to Ach.
Atropine blocks
Sympathetic Neurons
post ganglionic sympathetic fibers release NE
Parasympathetic Neurons
Post-ganglionic parasympathetic fibers release Ach
M3 receptor and the Eye
Contracts sphincter = miosis
Contracts ciliary bodies= accomodation
M2 receptor and the heart
Negative chronotropy. Dec HR= vagal arrest
Negative inotropy. Dec contractility
M3 receptor and the lung
Bronchospasm, inc. secretions
M3 receptor and the GI tract
Inc motility (cramps and diarrhea). Involuntary defecation
Tacrine
Centrally acting anticholinesterase and indirect cholinergic agonist (parasympathomimetic).
Tx: Alzheimers
Atropine
competitive Muscarin Ach R antagonist
“DOC w/ vagal arrest”
Glycoperrolate
Muscarinic receptor antagonist. Antispamodic
Tx: peptic ulcers
Pirenzepine
Muscarinic receptor antagonist. Antispasmodic.
Tx: peptic ulcers
Doxacurium
Most potent competitive non-depol NMJ receptor antagonist. No CV side effects. No histamine release
Beta-bungarotoxin
Prevent the release of Ach from vesicles at the presynaptic nerve terminal
alpha-bungarotoxin
Irreversible nicotinic receptor antagonist. Decreased action potentials
alpha1 & eye
contracts radial muscle= mydriasis (dilation)
alpha1 and arterioles
Constriction. Inc TPR= Inc diastolic pressure=Inc afterload
Alpha1 and venules
Constriction= Inc venous return= inc preload
alpha1 and sexual fct.
Ejaculation
Increased Diastolic Pressure
Inc alpha1= Inc TPR
Decreased diastolic pressure
Increased Beta2; direct acting vasodilators; cholinergics
Beta1 and heart
positive chronotropism = Inc HR
Positive inotropism= Inc contractility, Inc SV, Inc CO, Inc O2 consumption, Inc conduction velocity
Phenylephrine
Alpha 1 agonist.
Nasal decongestant
Beta2 agonist Asthma drugs
Metaproterenol; Albuterol; terbutaline; ritodrine; salmeterol
Ritodrine/turbutaline
Relaxes myometrium – used in premature labor pains
Phentolamine
Epinephrine reversal. Blocks alpha receptors, vasodilation occurs. Pt goes from hypertensive to hypotensive
Tx: pheochromocytoma to dec BP
Terazosin
Txt BPH (alpha 1 antagonist)
Yohimbine
Inc sympathetic outflow= alpha2 antagonist
Tx: impotence
Cardioselective NMJ
Pancuronium= Inc HR due to atropine-like antimuscarinic vagolytic effect and gallamine receptor antagonist— whaaat
Ecothiophate
Irreversible acetylcholinesterase inhibitor
-parasympathomimetic
Pyridostigmine
Cholinomimetic that increases muscarinic and nicotinic receptor effects. Acetylcholinesterase inhibitor and plasma cholinesterase inhibitor
DOC (drug f choice?) for the oral tx of MG
