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57 Cards in this Set
- Front
- Back
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Primary NT of the SNS
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NE
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Primary NT of the PNS
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ACh
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General effects of the PNS
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Responses are specific b/c postgang is short
Rest and Digest Miosis (constriction) Increase GI motility/salivation Increase urination/ defecation Decrease heart rate Bronchoconstriction Erection |
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General effects of the SNS
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Responses are diffuse b/c they have long postgang
Fight or flight Mydriasis (dilate) Decrease GI motility/salivation Decrease urination/defecation Increase heart rate Bronchodilate Ejaculation |
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Types Cholinergic (ACh) Receptors
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Muscarinic and Nicotinic
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Muscarinic Receptors
(Location and basics) |
Located at PNS nej, some SNS nej (sweat glands) and CNS
Activated by ACh and muscarine (poison) Found in body in greater numbers than nicotinic receptors |
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Effects of stimulating Muscarinic Receptors
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Mediated smooth muscle contraction (except sphincter contraction)
Stimulates gland secretions Decrease heart rate and conduction Bronchoconstriction Peripheral vasodilation Miosis SLUDGE |
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Nicotinic Receptors
(location and basics) |
Activated by ACh and nicotine
Located on autonomic ganglia and when activated will excite neurotransmission Located at somatic neuromuscular junction and when activated will mediate muscle contraction Some opposing effects of muscarinic (tachy, HTN) |
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Alpha1 adrenergic receptors
(location and basics) |
Constricts vascular smooth muscle
Constricts blood vessels Located at SNS nej (primarily smooth muscle) |
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Alpha 2 adrenergic receptors
(location and basics) |
Inhibition of NE release from nerve endings at presynaptic postgana neuron (negative feedback)
Also located on some postsyn tissue and blood platelets |
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Beta1 adrenergic receptors
(location and basics) |
Mediates cardiac stimulation (increase HR and contractility)
Located on SNS effector (cardiac muscle, vascular smooth muscle, renal cells to increase renin release) Increase lipolysis |
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Beta 2 adrenergic receptors
(location and basics) |
Mediates smooth muscle relaxation
Located in SNS effector (bronchioles in lung, uterine smooth muscle and vascular smooth muscle) In liver and muscle (mediated glycogenolysis, breakdown of glycogen to glucose) |
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MOA of direct agonists
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activate postsyn receptors
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MOA of indirect agonists
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stimulate release of NT
inihibit reuptake of NT inhibit metabolism of NT |
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MOA of direct antagonists
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block postsyn receptprs
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MOA of indirect antagonist
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inhibit synthesis of NT
prevent vesicular storage of NT inhibit release of NT |
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Cholinergic direct agonist
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Bind and activate cholinergic receptors
Choline esters Plant alkaloids |
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Cholinergic indirect agonist
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Increase synaptic concentrations of ACh
Cholinesterase inhibitors |
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Choline Esters
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Cholinergic direct agonists
ACh and carbachol: activate both nicotinic and muscarinic. They lack specificity for muscarinic subtypes therefore have a wide range of effects on many organ systems Bethanechol and methacholine: activates only muscarinic, but methacholine is not commercually available |
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Bethanechol (Urecholine)
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Cholinergic direct agonist
Acts at muscarinic ONLY Stimulates bladder without significant effects on HR or BP Used in TX of urinary retention post-op and post partum |
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Carbachol (Isoptocarbachol, miostat)
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Cholinergic direct agonist
For open-angle glaucoma Produce miosis during ophthalmic surgery |
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Plant alkaloids
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Cholinergic direct agonist
Muscarine: no current med use Nicotine: smoking cessation Pilocarpine:higher affinity fo muscarinic receptors, treats glaucoma by stimulating contraction of ciliary muscle fibers, this increases aqueous humor outflow which decreases intraocular pressure |
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Cholinesterase inhibitors
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Cholinergic indirect agonists
MOA: inhibit the breakdown of ACh at all cholinergic synapses, so ACH concentrations increase Can be reversible or irreversible |
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Donepezil (aricept)
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A reversible cholinesterase
treatment of Alzheimer's Disease |
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The 3 -stigmines
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Reversible cholinesterases
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Ecothiophate (Phospholine)
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Irreversible
Tx of chronic refractory glaucoma DOA of up to one week |
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Pesticides
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Irreversible
palathion and malathion |
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Soman
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Irreversible
chemical warfare agent |
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Organophosphate poisoning
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Irreversible cholinesterase inhibitor
Increased cholinergic neurotransmission at central and peripheral synapses Produces ALL effecets of muscarinic activation (SLUDGE, spasm, bronchconstriction, decrease HR & CO) Cholinergic activation in CNS - seizures, respiratory depression and coma Excessive activation of nicotinic receptors = neuromuscular blockade and muscle paralysis |
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Treatment of Organophosphate poisoning
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Symptomatic tx = maintain VS
Decontamination Antibodies: use atropine to counteract the ACh and pralidoime (2-PAM) to regenerate cholinesterase |
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Cholinergic antagonists
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Muscarinic anatagonists: plant alkaloids (atropine, scopalamine) and semi synthetic/synthetic (several)
Nicotinic antagonists: ganglionic blockers, neuromuscular blockers (curium), depolarizing neuromuscular blocker (succinylcholine) |
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BellaDonna alkaloids: atropine, scopolamine, hyoscyamine
Snythetic/semi synthetic: ipratropium, tolterodine, oxybutynin, propantheline, dicyclomine, benztropine |
BOTH types inhibit effects of PNS stimulation (smooth muscle relaxation, increase HR and cardiac conducation and inhibit exocrine gland secretion
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Ocular effects of muscarinic antagonists and therapeutic uses
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Relax iris sphincter (mydriasis), inhibits lacrimal gland (dry eyes)
Therapeutic uses: mydriatic to facilitate eye exam (atropine, troicamide, scopolamine) |
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Ocular effects of muscarinic antagonists and therapeutic uses
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increase HR and AV conduction
Therapeutic uses: sinus brachycardia, and AV block (atropine) |
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Respiratory effects of muscarinic antagonists and therapeutic uses
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Increase bronchodilation
Therapeutic uses: COPD, emphysema, bronchitis Ipratropium (atrovent) |
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GI and Urinary tract effects of muscarinic antagonists and therapeutic uses
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Relaxes GI muscle, reduces intestinal motility, inhibits gastric acid secretion and causes urinary retention
Therapeutic: treatment of intestinal spasms/pain (dicyclomine) and treatment of dysuria (painful urination) and urinary incontinence (oxybutynin: causes urinary retention) |
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CNS effects of muscarinic antagonists and therapeutic uses
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Sedation, confusion, altered mental status
Tx of motion sickness by blocking cholinergic transmission from vestibular apparatus to vomiting center Tx of Parkinson's disease, which reduces tremors |
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Nicotinic Antagonists
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Ganglionic blockers: limited due to adverse effects, trimethaphan is used rarely for hypertensive emergency
Neuromuscular blockign agents: nondepolarizing and depolarizing |
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Nondepolarizing nicotinic antagonists
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AKA curaruforms
Competitive antagonists of ACh at nicotinic muscle receptors Causes muscle relaxation and paralysis Effects reversed by cholinesterase inhibitors Used after surgery Atracurim, pancuronium (2nd ingredient in lethal injections), vecuronium |
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Depolarizing nicotinic antagonists
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Succinylcholine
Causes persistent depol Used for surgery (flaccid paralysis) Effect not reversed by cholinesterase inhibitors therefore not antidote if an overdose Short half-life Used if you need rapid intubation |
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Catecholamines
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Direct adrenergic agonists
Rapidly metabolized by monoamine oxidase (MAO) and catechol-o-methyltransferase (COMT) enzymes in gut, liver and other tissue - must give parenterally (in a manner other than through the digestive tract) Effects depend of affinity and specificity for type of adrenergic receptor |
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Direct adrenergic agonists: EPI
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Vasoconstriction & increase BP (alpha 1) dominates over B2 in blood vessel so you get more constriction than dilation
Cardiac stimulation (beta1) Bronchodilation & skeletal muscle vasodilation (beta2) Does bind to alpha 2, but no clinical application Used in anaphylactic shock and cardiac arrest |
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Direct adrenergic agonists: Norepi
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Vasoconstriction & increase BP (alpha1)
Cardiac stimulation (beta1) Used in hypotension and shock |
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Direct adrenergic agonists: dopamine
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Dopamine is a precursor to epi and norepi
Renal vasodilation (D1) Cardiac stimulation (beta1) Increase BP (alpha1) Used to TX cardiogenc shock, septic shock, heart failure and adjunct to fluid administration in hypovolemic shock |
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Direct adrenergic agonists non-catecholamines: Phenylephrine
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Neosynephrine
Vasoconstriction, increase BP and mydriasis (alpha1) Used as nasal decongestant, ocular decongestant and maintenance of BP during surgery |
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Direct adrenergic agonists non-catecholamines: Albuterol
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Proventil
Bronchodilation (beta2) Used in asthma |
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Direct adrenergic agonists non-catecholamines: Clonidine
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Catapres
Inhibits NE release from nerve terminal of postganglionic neuron (feedback inhibition: alpha2) Used to treat chronic hypertension Can have effects in CNS (sedation) Have anti-adrenergic effect, even though it is agonist |
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Direct adrenergic agonists non-catecholamines: Terbutaline
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Brethine
Bronchodilation and uterine relaxation (beta2) Used to tx asthma and premature labor (tocolytic) |
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Indirect adrenergic agonists: amphetamine
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Increase the release of NE & DA from SNS neurons
Vasoconstriction, cardiac stimulation and increase BP Penetrates CNS - CNS stimulation (increases mood and alertness (but decreases appetite) |
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Indirect adrenergic agonists: cocaine
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Local anesthetic
Stimulates SNS by blocking reuptake of NE and DA in the PNS and SNS - similar effect as amphetamine |
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Indirect adrenergic agonists: tyramine
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Normal by-product of tyrosine metabolism in body
Found in high concentrations in fermented foods such as certain cheeses, beers, red wine, certain cured meats (salami & pepperoni) Indirect sympathomimetic (sympathetic like effects, cause release of other catecholemines) b/c it causes the release of stored catecholamines. Normally metabolized by MAO. So if taking an MAO inhibitor must avoid tyramine-containing foods. |
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Mixed acting adrenergic
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Cause vasoconstriction by binding to alpha1
Increase release of NE from SNS neurons Nasal decongestants – Pseudoephedrine |
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Adrenergic receptor antagonists: Nonselective alpha-blockers
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Block alpha1 and alpha2 receptors
Phenoxybenzamine (Dibenzyline): Noncompetitive, irreversible; TX hypertensive episodes associated w/ pheochromocytoma (tumor in adrenal medulla that secretes Catecholamines) Phentolamine (Regitine) Competitive, reversible; DX and TX hypertensive episodes from pheochromocytoma Tx necrosis and ischemia from extravasations of epinephrine |
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Adrenergic receptor antagonists: Selective alpha1 blockers
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Azosin
Relax vascular smooth muscle and smooth muscle in bladder and prostate. Produce vasodilation and decrease BP Used to treat hypertension and urinary retention due to benign prostatic hyperplasia (BPH) Agents include: Doxazosin (Cardura), Prazosin (Minipress), Terazosin (Hytrin) Tamsulosin (Flomax) Alfuzosin (Uroxatral)– only for BPH not for HTN |
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Adrenergic receptor antagonists: Nonselective Beta-Blocker
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Block beta1 receptors in heart and beta2 in smooth muscle, liver and other tissues
Beta1 blockade - decrease BP , decrease cardiac output, decrease renin release and decrease aqueous humor secretion Beta2 blockade – bronchoconstriction, decrease glycogenolysis, mask signs of hypoglycemia, so diabetics won’t know when hypoglycemia (BAD)!! TX HTN, angina, arrhythmias, MI, migraine, glaucoma Agents include: Propranolol (used to treat migranes) (Inderal), Nadolol (Corgard), Timolol (Timoptic ) |
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Adrenergic receptor antagonists: selective Beta1 blockers
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Selective for beta1 receptors (primarily in cardiac tissue)
Produce less bronchoconstriction and other beta2 receptor mediated effects Aka cardioselective beta-blockers TX HTN, angina, MI, arrythmias Agents include: Metoprolol (Lopressor) |
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Mixed alpha and beta receptor antagonists
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Block both alpha and beta receptors
Carvedilol (Coreg): tx HTN and CHF Labetalol (Trandate): tx HTN |
