Autonomic & Somatic Nervous Systems Flashcards
What does sympathetic stimulation produces?
Increase in heart rate
Increase in blood pressure
RBCs pour into circulation from spleen
Blood flow shifts from skin & splanchnic region to skeletal muscle (causes pallor)
Blood glucose increases (glycogen in the liver is broken down into glucose, but insulin is also released)
Bronchiolar smooth muscle relax and pupils dilate
Intestinal smooth muscle relaxes but sphincters contract.
Activation of the renin-angiotensin-aldosterone system
What does cholinergic stimulation produce?
Salivation: stimulation of salivary glands
Lacrimation: stimulation of lacrimal glands
Urination: relaxation of internal sphincter muscle of urethra and contraction of the detrusor muscles
Gastrointestinal: upset. Smooth muscle tone causes GI problems (inc. diarrhea)
Emesis: vomiting
-Miosis: stimulation of papillary constrictor muscles.
What is Acetylcholine (ACh)?
Acetylcholine (ACh) is the neurotransmitter at the ganglia (both sympathetic and parasympathetic), at the postganglionic parasympathetic ending, and in the somatic nervous system.
What does acetylcholinesterase do?
breakdown Acetylcholine
What is Norepinephrine?
Norepinephrine is the neurotransmitter at the synapse between the postganglionic sympathetic neuron and the effector tissue. (Exception is the sweat glands where Ach is released).
What metabolizes NE?
metabolized by catechol O-methyltransferase (COMT) and monoamine oxidase (MAO) in the liver.
What is the difference between MAO-A and MAO-B?
MAO-A appears to be the important enzyme in depression and also the one responsible for adverse effects of MAO inhibitors
MAO-B is important in the metabolism of catecholamines in the brain. Selective inhibitors of MAO-B have been tried in Parkinson’s disease
What are the names of NE receptor sites?
alpha and beta
What are the effects of Alpha-1 stimulation?
Alpha-1 (postsynaptic) (causes contraction, e.g., blood vessels, sphincters, radial muscle of eye) (There are at least 3 receptor subtypes. α1A is found in the prostate gland; α1B is found in the wall of blood vessels.) Vasoconstriction Mydriasis Contraction of GI sphincters Contraction of bladder sphincter
What are the effects of Alpha-2 stimulation?
Alpha-2 (presynaptic) [negative feedback loop inhibiting subsequent release of neurotransmitter]
inhibits insulin release.
What are the effects of Beta-1 stimulation?
Beta-1 (predominately cardiac) Stimulation produces increase in heart rate and strength of contraction.
What are the effects of Beta-2 stimulation?
Beta-2 (predominately non-cardiac) receptors are found on smooth muscle [e.g., bronchi; large blood vessels] causing relaxation. Beta-2 receptors also promote insulin release and, in liver & muscle, gluconeogenesis & glycogenolysis as well as lipolysis in fat cells.
What are the effects of Dopamine-1 receptor stimulation?
Dopamine-1 (postsynaptic) receptor activation is responsible for vasodilation in splanchnic & renal circulations. Stimulation of dopamine receptors in chemoreceptor trigger zone causes nausea and vomiting.
What are the effects of Dopamine-2 receptor stimulation?
Dopamine-2 (presynaptic) receptors initiate a negative feedback loop. {At least five varieties of dopamine receptors are found in brain}
What are Acetylcholine (ACh) receptors?
Muscarinic and Nicotinic
How are Muscarinic receptors located?
Muscarinic - found at postganglionic parasympathetic endings (heart; smooth muscle; glands).
Where are Nicotinic receptors located?
Nicotinic receptors are found in ganglia and at neuromuscular junction. These are not identical, but are identified as
NM, receptors found at the neuromuscular junction in skeletal muscle.
NG or NN receptors found in autonomic ganglia, adrenal medulla, and CNS
What is Bethanechol (Urecholine)?
is a cholinomimetic that is somewhat selective to smooth muscle of the GI tract and the detrusor muscle of the urinary bladder, (It may have a relative affinity for specific muscarinic receptors in the gut). It also increases the tone of the lower esophageal sphincter in patients with reflux esophagitis.
What is Bethanechol (Urecholine) Side effects and contraindications?
Toxicity & side effects:
Initially: Abdominal discomfort, salivation, flushed skin, sweating, nausea, vomiting, and miosis are common.
Toxic reactions: include intense cramping, diarrhea, urination, bradycardia, and bronchoconstriction.
Contraindicated: COPD, asthma, hyperthyroidism, peptic ulcer.
What is Neostigmine and pyridostigmine?
produce reversible inhibition of AChE by formation
are used in the treatment of myasthenia gravis
What are the side effects of Neostigmine and pyridostigmine?
Side effects include nausea, diarrhea, and excessive salivation. Caution in patients with asthma. If muscarinic effects of such therapy are prominent, they can be controlled by the administration of atropine.
Differences between Neostigmine and pyridostigmine?
Pyridostigmine is generally preferred in myasthenia because of its longer duration of action (6 hr vs. 2 hr for neostigmine).
What is Donepezil HCl [Aricept]?
is a centrally acting reversible cholinesterase inhibitor leading to increased levels of acetylcholine in the brain. treatment of mild to moderate dementia of the Alzheimer’s type. Among those who benefit, improvements are seen in quality of life and cognitive functions (eg, memory, thought, reasoning)
What are Donepezil HCl [Aricept] side effects?
Side effects: Most side effects are related to increased cholinergic (muscarinic) effects including sialorrhea, nausea, vomiting, diarrhea, dyspepsia, urinary urgency myalgia, anorexia, ataxia, bradycardia, and bronchoconstriction.
atropine
Anticholinergic (antimuscarinic) drugs competitively antagonize the effects of ACh and other muscarinic agonists at cholinergic postganglionic (muscarinic) sites found in the heart, salivary glands & smooth muscle of the GI and GU tract (simply by binding to and blocking the receptor site)
is used to reverse severe sinus bradycardia
Scopolamine
Anticholinergic (antimuscarinic) drugs competitively antagonize the effects of ACh and other muscarinic agonists at cholinergic postganglionic (muscarinic) sites
has marked CNS depressant effects
What are side effects of Atropinic drugs?
Cardiovascular: The atria of the heart are richly innervated by parasympathetic nerve fibers, and the SA node is very sensitive to muscarinic receptor blockade. Large doses cause progressively increasing tachycardia by blocking vagal effect at the SA node pacemaker (average increase in heart rate: 35-40 beats/minute).
Gastrointestinal: Salivary secretion is particularly sensitive to inhibition by antimuscarinic agents.
Sweat glands: Small doses of atropine inhibit the activity of sweat glands.
Respiratory tract. Atropine decreases secretions in the nose, mouth, pharynx and bronchi. It also blocks vagal-induced bronchoconstriction.
Urinary tract: Muscarinic antagonists decrease normal tone and amplitude of contraction of the ureter and bladder.
Cyclopentolate [Cyclogyl] and tropicamide [Mydriacyl] are used for?
induction of mydriasis and cycloplegia for diagnostic procedures.
What is Glycopyrrolate?
Anticholinergic (antimuscarinic) drug
twice as potent as atropine in antisialagogue effect and has a longer duration of action
What is ipratropium [Atrovent]?
anticholinergic drug
effective bronchodilators administered by aerosol inhalation
Anticholinergic drugs are contraindicated in which patients? Why?
asthmatic patients because of drying of secretions and increased risk of mucus plugs
contraindicated in patients with glaucoma increased IO pressures
What is Oxybutynin? Adverse effects?
both an antimuscarinic and an antispasmodic
treats overactive bladder
easily crosses the blood-brain barrier, thus has a higher rate of CNS adverse effects.
adverse effects include xerostomia (70%) constipation, urinary retention, and blurred vision. Alcohol may enhance the drowsiness.
What is Tolterodine [Detrol]?
treatment of overactive bladder
activity is altered by enzyme inhibitors
may produce blurred vision, dizziness, or drowsiness.
What is scopolamine [Transderm-Scop]?
protect against motion-induced nausea without introducing prohibitive side effects such as sedation, cycloplegia, or drying of secretions.
What is benztropine?
tremor of Parkinson’s disease is reduced
What is dicyclomine [Di-Spaz; Bentyl]?
used for a wide variety of conditions involving increased spasticity and motility of the GI tract
What is Epinephrine? Side effects?
Treatment of life threatening allergic reactions
DOC in ACLS procedure
Toxicity & Side effects: May cause fear, anxiety, tension, restlessness, throbbing headache, tremor, dizziness, pallor, respiratory difficulties, tachycardia or palpitation.
What is Norepinephrine? Side effects?
potent alpha agonist (but less so than epi)
Side Effects: Similar to epinephrine (bradycardia, anxiety, & headache). Extravasation of the drug causes necrosis and sloughing of tissues. Relieve with hot packs and infiltration of phentolamine [Regitine], an alpha-1 blocker. (Black box warning of extravasation ischemia).
What is Dopamine?
is an important neurotransmitter in both the CNS (basal ganglia via presynaptic dopamine receptors) and periphery (vasodilation via postsynaptic dopamine-2 receptors in renal & mesenteric vasculature).
Increases cardiac output in patients with low blood pressure, atrial filling pressures, and low urine output. It is useful in cardiogenic and bacteremic shock.
What are Dopamine adverse effects?
tachycardia, dysrhythmias, and angina pain; the result from activation of beta-1 receptors in the heart.
What is Ephedrine?
a noncatecholamine; both an alpha and beta agonist
IV to increase blood pressure, orally in treatment of bronchial asthma, topically as a nasal decongestant.
What is Amphetamine and dextroamphetamine?
CNS stimulant and mood-elevating (euphoriant) effect, which is the basis for the widespread abuse of this drug.
Indicated for treating ADHD and narcolepsy in adults. The amphetamines have an alerting, sleep-deferring action that is manifested by improved attention to repetitive tasks. They depress appetite. They cause release of NE, dopamine & 5-HT from storage sites. (Adderall is a mixture of amphetamine and dextroamphetamine
What is Methylphenidate [Ritalin]?
amphetamine variant used in the treatment of ADHD
What is Pseudoephedrine [Sudafed]?
is a stereoisomer of ephedrine and is a decongestant found in many OTC preparations
indicated for temporary relief of nasal congestion due to hay fever, common cold, or other upper respiratory allergies
What are Pseudoephedrine [Sudafed] side effects? Which patients is it contraindicated in?
arrhythmias, tachycardia, headache, jitteriness, insomnia. The package will contain a warning not to take the drug if you have heart disease, high blood pressure, thyroid disease, diabetes, or difficulty in urination due to enlargement of the prostate gland
What is Phenylephrine [Neo-Synephrine]?
direct alpha receptor agonist with minimal effect on beta receptors.
results in vasoconstriction and may cause reflex bradycardia.
What is Albuterol?
relatively selective beta-2 agonist that, by aerosol, has a duration of 4-6 hours
For relief and prevention of reversible bronchospasm associated with asthma, bronchitis, emphysema, and COPD
Patients at risk include diabetics, hyperthyroidism, subjects with seizures disorders, and the elderly
What is Salmeterol?
LABA
is given 2 puffs q12h for maintenance of bronchodilation and prevention of symptoms of asthma. It is NOT used for rescue therapy in acute attacks.
prolonged use of long-acting beta receptor agonists and death from asthma (black box warning)
What is clonidine?
centrally acting alpha-2 agonist that acts as an antihypertensive drug
indicated for the treatment of hypertension and attention deficit hyperactivity disorder (ADHD)
Abrupt discontinuation of clonidine can result in rebound hypertension
Kapvay is a sustained release clonidine tablet approved for the treatment of ADHD.
What is methyldopa?
stimulates alpha-2 adrenergic receptors in the hypothalamus (centrally)
decreases in peripheral vascular resistance, heart rate, & blood pressure occur; however, compensatory sympathetic reflexes remain intact.
drug of choice for treating hypertension in pregnant women.
What is Phentolamine [Regitine]?
Treatment of acute hypertensive emergencies as may accompany intraoperative manipulation of pheochromocytoma or autonomic hyperreflexia.
used when a sympathomimetic (norepinephrine; dopamine) is accidentally administered extravascularly.
What are Prazosin [Minipress], Terazosin [Hytrin], Doxazosin [Cardura]?
selective α1- adrenoceptor antagonists
treat hypertension
Terazosin and doxazosin are also indicated for the treatment of symptomatic benign prostatic hyperplasia
Side effects include vertigo, fluid retention, and orthostatic hypotension. Other side effects occurring less than 1% of time are palpitations, nausea, CNS depression, drowsiness & headache. Marked hypotension and syncope (due to excess postural hypotension) may occur early in treatment (“first dose effect”, usually occurs within 30-90 min)
What is Tamsulosin [Flomax]?
specific prostatic α1A-adrenoceptor antagonist for BPH
What is Finasteride [Proscar]?
inhibitor of 5α-reductase
less efficacious than the alpha-1 antagonists and may take weeks or months to produce an effect. Finasteride is also marketed as Propecia for treatment of male pattern hair loss
Pregnancy Category X.
What is Sildenafil [Viagra]?
Sildenafil and related compounds are relatively specific for inhibiting PDE-5. Thus they improve erectile response to sexual arousal.
What are contraindications for Sildenafil [Viagra] and Tadalafil [Cialis]?
Contraindications: These agents are contraindicated in patients taking organic nitrates and alpha-1 antagonists and in men for whom sexual activity is inadvisable due to underlying CV status.
headache, dyspepsia, nasal congestion and back pain. Transient, dose-related impairment of color discrimination (blue/green) has been reported.
What is propranolol?
Nonselective, affects beta-1 and beta-2 (blocks)
Used for: Hypertension, angina pectoris, supraventricular arrhythmias, essential tremors, and migraine headache prophylaxis
What is metoprolol?
Selective for beta-1 receptors
Hypertension, angina, acute myocardial infarction and CHF
What is labetalol?
Beta blockers (nonselective) with alpha blocking activity
What is Timolol?
topically in treatment of glaucoma
What is Atenolol?
selective beta-1 antagonist
It is indicated for treatment of angina, hypertension & acute MI
What is Esmolol [Brevibloc]?
rapid onset short-acting selective beta-1 antagonist, useful for treating adverse blood pressure and heart rate responses that occur intraoperatively in response to noxious stimulation
What is Carvedilol [Coreg]?
selective alpha-1 antagonists and nonselective beta antagonists.
indicated for the treatment of hypertension
What is Nebivolol [Bistolic]?
3rd generation beta blocker with vasodilating properties
beta-1 selective but it releases nitrous oxide and is a vasodilator
contraindicated in severe bradycardia, greater than 1st degree heart block, and decompensated cardiac failure
What is Bupropion [Zyban SR]
approved for smoking cessation
stop smoking by boosting dopamine, serotonin, and norepinephrine, brain chemicals also boosted by nicotine and associated with craving and withdrawal symptoms
What is Varenicline [Chantix]?
oral treatment of tobacco dependence
What is Tubocurarine?
“Competitive” or nondepolarizing agents bind to the ACh-n receptor (NM), competitively blocking the action of ACh and immediately reducing muscle activity.
What is Succinylcholine?
“Competitive” or nondepolarizing agents bind to the ACh-n receptor (NM), competitively blocking the action of ACh and immediately reducing muscle activity.
two acetylcholine molecules attached
Treat hyperthermia with dantrolene
