Autonomic Pharmacology Flashcards

Terms Definitions
indirect-acting sympathomimetic
Alpha-1 Antagonist
Carbamate AChE inhibitor
phenylephrine, methoxamine, norepinephrine
Ganglion blockers
hexamethonium, mecamylamine
cholinergic antagonist (muscarinic only)
inhibits synthesis of acetylcholine
cholinergic agonist (muscarinic only)
MAO (monoamine oxidase) inhibitor
Direct-acting sympathomimetic: α1, α2, β1
Muscarinic antagonist, causes mydriasis for eye exams
'Amphetamine-like' Indirectly releases NE, direct Beta-2 agonist and alpha-1 agonist. Anorexigenic
dobutamine mechanism
relatively selective b1-agonist
stretch-sensitive mechanoreceptors in the carotid arteries transmit information via what nerve?
Neurotransmitter of parasympathetic postganglionic fibers is what?
nonselective beta adrenoceptor agonistused to treath asthmaSympathomimetics -Catecholamine - selective for B, treat asthma
Depolarizer Neuromuscular Receptor Antagonist
Choline Esters
Acetylcholine, Methacholine, Carbachol, Bethanechol
Dx of bronchial hyperreactivity
selective β1 adrenergic antagonist; extremely short half-life; used for emergencies
indirect agonist at α1, β1
reverses noradrenergic Reuptake I, increasing NE release
Terbutaline is used for?
Acute ashtma
Irreversible AChE inhibitor-> causes miosis
Reversibly binding, alpha-1 and alpha-2 antagonist.
Which modulatory receptor increases release of additional norepinephrine?
only widely available, relatively specific a2-antagonist
Arterioles b2 NE what response?
Arterioles a1,a2 NE what response?
Cardiac stimulation, Gs protein
Andrenergic Agonists (sypathomimetics)
Catecholamines, Non-catecholamines, Beta-2, and Alpha-2
Selective β1 blockers
Acebutolol, atenolol, metroprolol
Rx of muscarinic blocker intoxication
β1 agonist; increases heart contraction, to treat low cardiac output, short-acting
Phenylphrine affects which receptors?
Alpha-1 AGONIST only
Botulinum toxin
Destroys SNARE proteins, prevents transmitter release
Muscle relaxant, less sedative than Diazepam or Baclofen
Dobutamine affects which receptors?
Beta-1 receptors only
Beta-2 AGONIST, used for acute asthma
Beta-2 AGONIST, for chronic asthma, always given with a steroid
Adipose Tissue a2 NE effect?
Reduced lipolysis
eccrine sweat glands are stimulated by what neurotransmitter
monoamine oxidase (MAO) breaks down what neurotransitter?
Dosazosin, prazosin, terazosin
alpha-1 selective adrenoceptor antagonistused to treat hypertension
Muscarinic receptor antagonists
atropine, glycopyrrolate, N Butylscopolammonium Bromide
Uses of atropine
Anesthesia, management of organophosphate toxicity
α1 effects
Mydriasis, increases TPR, diastolic pressure, afterload, venous return, preload, reflex bradycardia, urinary retention, ejaculation, glycogenolysis, decreases renin release
Direct muscarinic agonists
ACh, bethanecol, methacholine, pilocarpine
Beta 2 AGONIST, relaxes uterus, to delay delivery of premature babies
Tyramine mechanism
enters noradrenergic neurons via the norepinephrine transporter and displaces NE from the "labile pool" (non-stored NE) and into the synaptic cleft onto postsynaptic receptors
hydrolysis of ACh into choline and acetic acid is catalyzed by which enzyme
interventions which inhibit monamine oxidase
pargyline, tranylcypromine, selegiline
the rate-limiting step in NE synthesis and is located in which cell compartment?
the cytoplasm
____ is a neurochemical mediator in the central nervous system and probably also in some neurons in the superior cervical ganglion and the kidney.
Cholinomimetic Drugs (parasympathomimetics)
Direct (receptor Agonists) and Indirect (cholinesterase Inhibitors) Acting
β blockers used as antiarrhythmics
Propranolol, acebutolol, esmolol
Norepinephrine is especially potent at which adrenoreceptors.
a1 and at b3
reason for methyldopa use as antihypertensive
its metabolite, a-methylnorepinephrine, stimulates a2 receptors
inhibition and stimulation of Phenylethanolamine-N-methyltransferase (norepinephrine to epinephrine)
inhibited by physiological concentrations of epinephrine Glucocorticoid increases enzyme activity.
Pupil a1 --NE what response?
Mydriasis (radial muscle contraction)
Uses of isoproterenol
β1=β2: used in bronchospasms, heart blocks and bradyarrhythmias. Side effects: flushing, angina, arrhythmias
Uses of dobutamine
β1 > β2: congestive heart failure
diagnosis and localization of Horner's syndrome
documenting that an a1-adrenoreceptor agonist (phenylephrine) will dilate the patient's constricted pupil. Hydroxyamphetamine, a tyramine-like agent, will also dilate the pupil if the neuron innervating the iris is intact (that is, if the lesion is more central). If the most peripheral nerve is the damaged one, hydroxyamphetamine will not work.
Combined α1 and β blockers
Labetalol, carvedilol. Used in CHF.
Dopa decarboxylase "aromatic-L-amino acid decarboxylase" (dopa to dopamine) is found in what cell compartment of what tissues?
cytoplasm of many nonneural as well as neural tissues
Effects of β1 blockers
Decresed HR, SV, CO, renin, aqueous humor production
During increased sympathetic stimulation, dopa production is increased in what ways?
a) more enzyme is synthesized, and b) the physical properties of the enzyme are altered (allosteric activation) so that affinity for tyrosine is increased and affinity for end products like NE is reduced
The circadian rhythm of autonomic function originates where?
suprachiasmatic nucleus (SCN) in the hypothalamus
Muscarinic receptors of the eye
Sphincter of the pupilla and cilliary muscles --> M3 --> miosis and accomodation
Muscarinic receptors of sphincters (GI, GU)
M3 --> relaxation, excep LES which contracts
foods which are dangerous for patients on inhibitors of monoamine oxidase
patients on inhibitors of this enzyme (e.g., pargyline) may have profound hypertension from over-indulgence in tyramine-containing foods.--such as cheddar cheese, certain wines, marmite, country ham, and broadbeans (fava beans).
Muscarinic receptors of the heart
SA node and AV node --> M2 --> decrease heart rate, decrease conduction velocity
Alpha-2 antagonist
Blocks UPTAKE 1
Selective Beta-2 Blocker
Uses of propicamide
noradrenergic agonist (alpha-1 only)
non-selective β adrenergic antagonist; long-acting
Direct-acting sympathomimetic: less β1, more β2; treat acute asthma, fast-acting, short duration
Nicotinic muscle (Nm) ANTAGONIST
Destroys vesicle, depletes NE
Phenylephrine (Neosynephrine®) and methoxamine are far more potent in stimulating which receptors
bronchodilation, Gs protein
Alpha-2 Antagonists
Yohimbine, Tolazoline, Atipamezole
Nonselective α blockers
Phentolamine, phenoxybenzamine
inhibits peripheral COMT (inactivates L-DOPA); increases amount of circulating L-DOPA
prototype DIRECT-acting drug (combine directly with the receptor to produce a response; also removed from terminal by Uptake 1); α1, α2, β1, β2
Carbonic anhydrase inhibitor (for glaucoma)
Selective antagonist for Alpha-1 (allows alpha-2 feedback, prevents tachycardia from overstimulation with NE)
Norepinephrine affects which receptors?
Alpha-1/2, Beta-1
intervention which inhibits dopa decarboxylation
clonidine, guanabenz, guanfacine, and a-methylnorepinephrine
Pancreas ß2 NE effect?
Increased insulin
phentolamine, phenoxybenzamine
Nonselective alpha adrenoceptor antagonistused to treat hypertensionSympatholytics - a-blocker, used to treat hypertension
Non Selective Alpha Antagonists
Phenoxybenzamine, Tolazoline
Curare Alkaloid Neuromuscular Receptor Antagonist
Located in postsynaptic membrane, degrades catecholamines by methylations (requires SAM).
selective Alpha-1 antagonist, used to treat benign prostatic hyperplasia (urinary retention)
Beta-1 and Beta-2 antagonist, also Alpha-1 blocker.
Interferes with central SNS outflow, stimulate CNS Alpha-2 receptors
muscarinic antagonist, used as aerosol to relax lungs in ppl with COPD
Bladder sphincters are contracted by stimulation of what receptor
a1-blockers, 4
1 prazosin2 phentolamine3 tolazoline4 phenoxybenzamine
uptake II
uptake of catecholamines into extraneuronal tissue
Phenoxybenzamine clinical use
medical management of pheochromocytoma.
acetylcholine stimulates release of NE from postganglionic neuron via what receptor
nicotinic receptor
Efferent parasympathetic outflow to the cardiovascular system goes through what nerve?
vagus nerve.
name the catecholamines
Norepinephrine, epinephrine and dopamine
propranolol, nadolol, pindolol
nonselective beta adrenoceptor antagonistused to treat hypertensionsympatholytics - b-blocker, nonselective, used to treat hypertension
Cholinergic Antagonists (parasympatholytic, Anticholinergic)
Ganglionic Receptor Antagonists, Muscarinic Receptor Antagonists, Neuromusclular Receptor Antagonists (spasmolytics)
D1 effects
Vasodilation of renal, mesenteric, coronary vasculatures, increases RBF, GFR
Selective α1 blockers
Prazosin, doxazosin, terazosin, tamsulosin
Alpha-methyl Tyrosine
Inhibits synthesis of DA (thus inhibiting synthesis of NE)
prazosin receptor stimulation
selectively block the a1- receptor
treatment of Dopamine-ß-hydroxylase deficiency
dihydroxyphenylserine (DOPS), which is decarboxylated directly into norepinephrine by dopa decarboxylase, thus restoring the appropriate neurotransmitter
The primary neurochemical mediator of both sympathetic and parasympathetic preganglionic neurons is what?
acetylcholine (ACh).
Uses of α blockers
Hypertension, pheochromocytoma, BPH (selective α1 blocker)
AChE inhibitor, works in CNS to delay Alzheimer's disease
Epinephrine clinical use
to support blood pressure, especially during anaphylaxis
Direct Acting Cholinomimetics (receptor Agonists)
Choline Esters and Natural Alkaloid
β blockers that cause the most sedation
Propranolol, timolol
Both 'D' and 'L' isomers. Act the same in the periphery to indirectly release NE. In CNS D isomer is 3-4x more potent. Releases DA to stimulate CNS.
timolol clinical use
eye drops are used in glaucoma patients to reduce intraocular pressure
Excitatory neurons from the nucleus tract solitarii (NTS) innervate what?
the dorsal motor nucleus
Distribution of α1 receptors
Pupil dilator muscle, arterioles of skin and viscera, veins, bladder trigone and sphincter, vas deferens, liver, kidney
Muscarinic receptors of glands
M3 --> gland secretion --> sweat, salivation, lacrimation
Muscarinic receptors in endothelium
M3 --> cause vasodilation via release of NO
The major problems in prazosin use
prazosin syncope," fainting that occasionally occurs on standing 2-4 hours after the first oral dosetendency toward reduced efficacy with chronic use
β blockers with intrinsic sympathomimetic activity
Act as partial agonists, less bradycardia, slight vasodilation, bronchodilation, minimal change in lipids: acebutolol, pindolol
Properties and use of pilocarpine
Acts on muscarinic receptors. Not hydrolyzed by AChE. Used for Rx. of glaucoma and xerostomia.
non-specific cholinesterase (pseudocholinesterase or butyrylcholinesterase) is found where?
in plasma and in some organs but not in the red blood cell or the cholinergic neuron.
stretch sensitive receptors transmit information to where in CNS?
nucleus tract solitarii (NTS) in the posterior medulla.
Distribution of β1 receptors
Heart SA node, AV node, atrial and ventricular muscle, His-Purkinje, kidney
Receptors in the adrenal medulla
Nn --> secretion of epinephrine and norepinephrine
Properties and use of neostigmine and pyridostigmine
Cuaternary amines AChE inhibitors. Rx paralytic ileus, urinary retention, myasthenia, reversal of nondepolarizing NM blockers
Effects of medium dose epinephrine on CV and respiratory systems
Acts on β1 (increases HR, SV, CO, pulse pressure), β2 (decreases TPR, BP, bronchodilation), α1 (increases TPR, BP)
blocks NE release
Spleen Capsule a1
Benzylisoqionoline Neuromuscular Receptor Antagonist
β agonists
Isopreterenol, dobutamine
non-selective α adrenergic antagonist; irreversibly bound
Reverses 'irreversible AChE inhibitors' such as organophosphates, when used quickly
AChE (Acetylcholine Esterase) Inhibitor
increase release of norepinephrine
nonselective beta adrenoreceptor agonistSympathomimetics -Catecholamine - nonselective beta adrenoreceptor agonist
Naturally occurring and Synthetic
Natural Alkaloid
Pilocarpine and Muscarine
Irreversible inhibitors
organophosphate compounds-Diisopropyl phosphorofluoridate, dichlorvos
Specific uses of timolol
Rx Alzheimer disease
Donepezil, tacrine
inhibits enzyme decarboxylase in periphery, reducing the effects of dopamine in the periphery; usually given with L-DOPA; allows more to pass BBB to replace DA in Parkinson's
Muscarinic antagonist- relief from overactive bladder
Carbamate AChE inhibitor, insecticide used for head lice
intervention which results in acetylcholine precursor transport blockade?
sretch sensitive mechanoreceptors in the aorta transmit information via what nerve?
propranolol affect on AV conduction
Uterus b2 NE what response?
Liver a1, b2 NE effect?
motor neuron -< skeletal muscleName:neurotransmitter/receptor type of skeletal muscle
atenolol, acebutolol
beta-1 selective adrenoceptor antagonistused to treat hypertensionsympatholytics - b1-selective, used to treat hypertension
Beta-2 Andrenergice Receptor Agonists
Albuterol/Clenbuterol, Metaproteranol/terbutaline/Salmeterol...
Naturally Occurring Catecholamines
Epinephrine, Norepinephrine, Dopamine
Located in outer mitochondrial membrane, degrades catecholamines by oxidative deamination. MAO-A: mainly in liver metabolizes NE, 5HT and tyramine. MAO-B mainly in brain, metabolizes DA.
direct muscarinic agonist; used to open the drainage angle in the eye, decreasing IOP
Alpha-2 agonist (reduces aqueous humor production, for glaucoma)
Adipose Tissue b3 NE effect?
Heat production
presynpatic adrenergic receptor, Gi protein
Uses of clonidine
Mild to moderate hypertension
β1 effects
Increases HR, conduction velocity, contractility, CO, oxygen consumption and renin release
Metoprolol mechanism
relatively selective blocker of the b1-receptor
Acetylcholine (ACh) is synthesized by what?
choline acetyltransferase
Phenylethanolamine-N-methyltransferase (norepinephrine to epinephrine) is restricted to where?
adrenal medulla, the brain and the organ of Zuckerkandl
inhibitors of monamine oxidase
pargyline, tranylcypromine, and selegiline (Deprenyl®)
what is cotransmission ?
multiple neurotransmitters commonly exist within one neuron, and they may be differentially released
Non Depolarizers (competitive)
Curare Alkaloids, Ammonio Steroids, Benzylisoquinolines
α2 effects
Decreases NE synthesis and release, promotes platelet aggregation, decreases insulin secretion
Distribution of D1 receptors
Renal, mesenteric, coronary vasculature
P1 receptor
adenosine acts on receptor (ATP post metabolism)
mechanism of yohimbine
By blocking a2-adrenoreceptors in the medulla, it increases sympathetic outflowBy blocking presynaptic a2-adrenoreceptors in the periphery, it enhances norepinephrine release
How are Phenylephrine (Neosynephrine®) and methoxamine used clinically?
hypotensive stateslocally to cause mydriasisnasal congestionsPhenylephrine is occasionally used to restore paroxysmal atrial tachycardia to normal sinus rhythm (via baroreceptor-mediated enhancement of vagal tone).
Catechol-o-methyltransferase (COMT) function and location
converts NE into normetanephrine and epinephrine into metanephrinefound especially in liver and kidney.
Skeletal Muscle Relaxers (spasmolytic agents)
Neuromuscular Receptor Antagonists, Centrally acting, and peripherally acting
Mechanism of accomodation
Ciliary muscle has M3 receptors. Muscarinic agonists cause contraction and widening of the lens for close vision. Muscarinic antagonists cause cycloplegia and stretching of the lens for far vision.
Effects of β2 blockers
Bronchospasm in asthmatics, vasospasm, decreased glycogenolysis, gluconeogenesis, increased LDLs, TGs
Distribution of β2 receptors
All blood vessels, uterus, bronchioles, skeletal muscle, liver pancreas
clinical effect of pseudocholinesterase deficiency
some drugs such as succinylcholine (used during anesthesia) which are normally broken down by pseudocholinesterase, are very poorly metabolized by this variant enzyme. Such patients may have prolonged muscle paralysis from succinylcholine
what is a clinically useful inhibitor of tyrosine hydroxylase? Why significant enzyme?
metyrosine (a-methyl-p-tyrosine).rate limiting step of NE synthesis
Combined K channel and β blockers
Sotalol. Class III antiarrhythmic.
Inhibitory neurons of the nucleus tract solitarii (NTS) innervate what?
Excitatory neurons innervate the dorsal motor nucleus of the vagus, where parasympathetic outflow is regulated. Inhibitory neurons, using gamma- aminobutyric acid (GABA) as neurotransmitter, innervate areas in the ventrolateral medulla from which sympathetic outflow is regulated. The most important such site is the rostral ventrolateral medulla (RVLM).
Muscarinic receptors of the bladder
M3 --&gt; contraction of detrusor, relaxation of the trigone/sphincter --&gt; urination and urinary incontinence
Mechanism of miosis
Sphincter muscle of the pupilla has M3 receptors. Muscarinic agonists causes contraction and miosis. Muscarinic antagonists cause relaxation and mydriasis with cycloplegia.
Properties and use of physostigmine
Tertiary amine AChE inhibitor. Rx glaucoma, antidote in atropine overdose
Which drug may cause 'epi-reversal', a drop in blood pressure, if administered before Epinephrine?
Phentolamine (alpha-1 blocker), which prevents vascular constriction
propranolol affects on heart rate, contractility, and BP
In persons on no medication, propranolol reduces heart rate, contractility and blood pressure
Properties and use of bethanecol
Acts on muscarinic receptors. No AChE hydrolisis. Rx.: paralytic ileus, urinary retention
intracellular effect of activation of beta-adrenoreceptor
synthesis of cAMP by adenylyl cyclase **The hormone-receptor ("liganded receptor") interacts with a stimulatory guanine nucleotide-binding regulatory protein (Gs), which then activates the adenylyl cyclase.
Effects of β agonists on CV system
β1: increase HR, CO, pulse pressure; β2: decrease TPR, BP.
Effects of high dose epinephrine on CV and respiratory systems
Acts on α1 (increases TPR, BP), β1 (increases HR, CO, pulse pressure), β2 (decreases TPR, BP, bronchodilation). Potential reflex bradycardia.
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