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COM: Neuro II (Exam I) > Adrenergic Drugs > Flashcards

Flashcards in Adrenergic Drugs Deck (82):

What adrenergic receptors utilize a Gq protein and increase IP3 and DAG?

Alpha 1


What adrenergic receptor type utilizes Gi protein and decreases cAMP production?

Alpha 2


What adrenergic receptor type utilizes Gs protein and increases cAMP production?

All beta receptors


What dopamine receptors utilize a Gs protein and increase cAMP production?

D1 and D5


What dopamine receptor types utilize a Gi protein and decrease cAMP production?



List the 2 alpha agonist drugs and specify which receptor each is selective for

Phenylephrine specific or alpha 1 receptors
Clonidine specific for alpha 2 receptors


List the 2 mixed alpha and beta receptor agonist drugs and which receptors they are selective for

NE alpha 1 and 2 equally, prefers beta 1

Epi both alpha and betas equally


List the 4 beta receptor agonist drugs and which receptors they are selective for

Dobutamine beta 1
Isoproterenol both betas equally
Terbutaline beta 2
Albuterol beta 2


List the 2 dopamine receptor agonist drugs and which receptors they are selective for

Dopamine D1 and 2 equally

Fenoldopam D1


List the tissues that alpha 1 receptors are located on

Most vascular SM
Pupillary dilator muscle


List the actions of alpha 1 receptors

Contraction of muscles
Dilates pupils


List the tissues that alpha 2 receptors are located on

Postsynaptic CNS neurons
Adrenergic and cholinergic nerve terminals
Some vascular smooth muscle
Fat cells


List the actions of alpha 2 receptors

Aggregation of platelets
Inhibit NT release
Contraction of some vascular SM
Inhibits lipolysis


List the tissues that beta 1 receptors are located on

Heart and juxtaglomerular cells


List the actions of beta 1 cells

Increases force and rate of contraction of the heart and increases renin release from JG cells


List the tissues that beta 2 receptors are located on

Respiratory, uterine and vascular SM
Skeletal muscle
Human liver


List the actions of beta 2 receptors

SM relaxation
Potassium uptake
Activates glycogenolysis and gluconeogenesis


List the tissues that beta 3 receptors are located on

Fat cells


List the actions of beta 3 receptors

Relaxes detrusor muscle of the bladder
Activates lipolysis


List the tissues that D1 receptors are located on



List the actions of D1 receptors

Dilates renal blood vessels


List the tissues that D2 receptors are located on

Nerve endings


List the actions of D2 receptors

Modulates NT release


What receptors is epinephrine specific for

All alpha and beta equally


What effects does epinephrine have on cardiac function and what receptor is affected?

Affects the Beta 1 receptor

Causes increased forced of contraction, increased heart rate, and increased conduction velocity at AV node


What effects does epinephrine have on vascular tone and what receptors is it acting on?

Acting on beta 2 and alpha 1 receptors

Increases systolic BP
May decrease diastolic BP and total peripheral vascular resistance
Mean arterial pressure remains unchanged


Epinephrine affects vascular tone by acting on both beta 2 and alpha 1 receptors. There are significant differences in receptor types found in vascular beds. What receptor types are found in skin vessels and mucous membranes vs skeletal muscle vs renal and cerebral vascularture?

Skin vessels and mucous membranes = mostly alpha 1

Skeletal muscle = alpha 1 and beta 2

Renal, cerebral = D1 and alpha 1


What effects does epinephrine. Have on the respiratory system and what receptors are affected?

Relaxes bronchial muscle via beta 2 receptor

Decreases bronchial secretion and congestion’s within bronchial mucosa via alpha 1 receptor


What effects does epinephrine have on skeletal muscle and what receptor type is affected?

Affects beta 2 receptors

Causes muscle tremor and increases K+ uptake by skeletal muscle (promoting hypokalemia and decreasing K+ excretion by kidneys)


What effect does epinephrine have on blood glucose levels and what receptor type is affected?

Enhances liver glycogenolysis and gluconeogenesis via beta 2 receptors


What receptor types is norepinephrine specific for?

Alpha 1 and 2 equally but prefers Beta 1 over beta 2


What effects does norepinephrine have?

Potent cardiac stimmulant by reduces heart rate (bradycardia is an indirect effect)

Potent vasoconstrictor

Increases peripheral vascular resistance and BP

Role of baroreflex

**lacks beta 2 agonist effects so no bronchodilator and vasodilation**


What receptor types is phenylephrine specific for?

Alpha 1


What are the effects of phenylephrine?

Effective mydriatic and decongestant

Causes severe3 vasoconstriction, BP elevation and severe bradycardia (indirect effect bc it doesnt affect any beta receptors)

Role of baroreflex


What receptor types is clonidine selective for?

Alpha 2


What are the effects of clonidine?

Central effect on alpha 2 receptors in the lower brainstem area causing decreased sympathetic outflow, reduced BP and bradycardia

Local application produces vasoconstriction


What receptor type is isoproterenol specific for?

Beta 1 and 2 equally


What are the effects of Isoproterenol on beta one receptors?

Positive inotropic and chronotropic action, increases cardiac output


What are the effects of isoproterenol on beta 2 receptors?

Vasodilator, decreases arterial pressure

Causes bronchodilation


Where is the main location of action of dobutamine?

THe heart -> increases HR but not as severely as isoproterenol


What is the most important adrenergic agonist for treating tachycardia?



What are the affects of terbutaline and albuterol?

Cause bronchodilation and relaxation of the uterus


What is the action of dopamine on D1 receptors?



Where is there a high density of D1 receptors?

Renal, cerebral, mesenteric and coronary vessels


What effect does activation of presynaptic D2 by dopamine have?

Suppresses NE release


What receptor types is dopamine able to activate at higher and higher doses

Activates beta 1 receptors in heart at higher doses

At still higher doses stimulates vascular alpha 1 AR to cause vasoconstriction -> elevates BP; this would be a similar affect to NE or epi


What adrenergic agonist is the best to treat heart failure?



List clinical uses of adrenergic agonists

Hypotension and shock
Heart failure
Emergency therapy for complete AV block & cardiac arrest
Decongestion of mucous membranes
Bronchial asthma
Ophthalmic applications = induction of mydriasis, glaucoma
Genitourinary applications = urinary incontinence, priapism
CNS applications = narcolepsy, ADHD, obesity


WHat are the adverse CV effects of adrenergic agonists?

Elevation in BP

Increased cardiac work may precipitate myocardial ischemia and heart failure

Sinus tachycardia and serious ventricular arrhythmias, May induce sudden cardiac death


What are some CNS toxicities that adrenergic agonists can cause?

Lack of appetite
Anxiety, restlessness
Psychoses (paranoid state, hallucinations)
Convulsions and hemorrhagic stroke (cocaine)


What are the effects of alpha antagonists on the CV system?

Decreased peripheral vascular resistance and BP

Postural hypotension

Reflex tachycardia


What are the effects of alpha antagonists on the GU system?

Relaxation of SM in prostate

Decreased resistance to the flow of urine


What is the clinical use of alpha antagonists?

Pheochromocytoma (tumor of the adrenal medulla producing catecholamines)

Chronic HTN

Erectile dysfunction

Benign prostate hyperplasia (to treat chronic urinary obstruction)


List the adverse seffects of alpha antagonists

Postural hypotension (antagonism of alpha 1 in venous SM)


Retention of fluid and salt

Impaired ejaculation

Nasal stuffiness

**seen less with alpha 1 selective antagonists**


Beta blockers with intrinsic sympathomimetic activity (ISA) are ________________ at beta adrenergic receptors

Partial agonists -> they block sympathetic effects but have submaximal effects of their own = a blunted sympathetic response

**Less risk for bradycardia, increase in VLDL/HDL, and other effects of beta receptor blockade


What pharmacodynamic effects do beta blockers have on the heart?

Negative inotropic and chronotropic effect

Block AV node -> slowed AV conduction and increased PR interval


What pharmacodynamic effects do beta blockers have on blood vessels?

Initially cause a rise in peripheral vascular resistance

Chronic use = decrease in PVR (lowers BP in HTN pts


What pharmacodynamic effects do beta blockers have on the renin-angiotensin system?

Inhibit renin release


What pharmacodynamic effects do beta blockers have on the respiratory system

Increase airway resistance


What pharmacodynamic effects do beta blockers have on the eye

Reduce production of aqueous humor reducing intraocular pressure


What pharmacodynamic effects do beta blockers have on the metabolic system?

Inhibit lipolysis

Increase VLDL and decrease LDL, reduce HDL cholesterol/LDL cholesterol ratio

Inhibit glycogenolysis and gluconeogenesis


List the clinical uses for beta blockers

Angina pectoris
Cardiac arrhythmias
Heart failure


List the adverse effects of beta blockers

Sedation, sleep disturbances, depression

Trigger bronchospasm and asthma attack in susceptible pts (COPD, asthma, chronic bronchitis)

Depression of HR and cardiac contractility

Increase VLDL and decrease HDL when used chronically

Exacerbation of peripheral vascular disease

May cause or exacerbate hypoglycemia in type 1 DM on insulin


Which of the following drugs acts directly on receptors located on the autonomic effector cell?
A. Amphetamine
B. Phenylephrine
C. Cocaine
D. Metyrosine
E. Guanethidine

B. Phenylephrine

All the others are indirect acting drugs; phenylephrine is the only direct acting drug


A healthy 25yo male is given an injection of NE. His BP increases from its resting value of 115/75mmHg to a transient value of 152/100mmHg. Which of the following cellular actions is the most likely cause of this increase in mean arterial pressure?
A. Activation of Gs in arteriolar smooth muscle
B. Activation of PLC in arteriolar SM
C. Arteriolar SM depolarization
D. Inhibition of AC activity inn arteriolar SM
E. Increased receptor autophosphorylation in arteriolar SM

B. Activation of PLC in arteriolar SM

**NE causes increased BP via activation of alpha 1 receptors which utilize Gq signaling


Dilation of vessels in skeletal m., constriction of cutaneous vessels and direct positive inotropic and chronotropic effects on the heart are all actions of:
A. Phentolamine
B. Epi
C. Isoproterenol
D. Terbutaline

B. Epinephrine

**dilation of vessels in skeletal m is beta 2, constriction of cutaneous vessels is an alpha1 effect


A 53yo pt suffering from postural hypotension was admitted to the hospital for evaluation. A tyramine infusion did not raise BP, whereas a very small dose of NE caused a large, transient elevation of BP. These results would suggest a degeneration of which of the following structures?
A. Postganglionic sympathetic neurons
B. Preganglionic sympathetic neurons
C. Postganglionic parasympathetic neurons
D. Preganglionic parasympathetic neurons
E. Adrenoceptors on vascular SM cells

A. Postganglionic Sympathetic Neurons


To facilitate an eye exam you want to cause mydriasis, but not alter normal control of accommodation. All of the following drugs are available as topical ophthalmic formulations. Which one will dilate the pupil without altering accommodation?
A. Atropine
B. Isoproterenol
C. Phenylephrine
D. Pilocarpine
E. Timolol

C. Phenylephrine

**Phenylephrine is an alpha1 agonist which is responsible for pupil dilation


What does contraction of the iris circular muscle cause and what receptors are responsible for this?

Constricts the pupil causing miosis; this is due to activation of M3 receptors


What does contraction of the iris radial muscle cause and what receptor is responsible for this?

Dilates pupil, causing mydriasis; effect is due to activation of alpha1 adrenergic receptors


What does contraction of the ciliary muscle of the eye cause and what receptor is responsible for this?

Causes accommodation of the eye to near vision; M3 receptors contract this muscle


When a moderate pressor dose of NE is given after pretreatment with a large dose of atropine, which of the following is the most probable response to NE?
A. A decrease in HR caused by direct cardiac effect of NE
B. A decrease in HR caused by indirect reflex effect of NE
C. An increase in HR caused by direct cardiac effect of NE
D. An increase in HR caused by indirect reflex effect of NE
E. No change in HR

C. An increase in HR caused by direct cardiac effect of NE

**B would be the correct answer if atropine wasnt in the picture


Between your 1st. And 2nd yr of med school you went abroad on a volunteer medical mission to a remote underserved area. Their drug selection is limited. A pt presents wwith acute cardiac failure, for which your preferred drug is dobutamine. However, there is none available. Which other drug, or a combination of drugs, would be a suitable alternative, given the pharmacological equivalent of what you want dobutamine to do?
A. Dopamine at a low dose
B. Ephedrine
C. Ephedrine + propranolol
D. NE + phentolamine
E. Phenylephrine + atropine

D. NE + Phentolamine

**Here you want the dobutamine to enhance heart contractility via Beta1 receptors and NE activates alpha receptors and beta1 receptors then the phentolamine with block the activated alpha receptors leaving you with just the activation of Beta1 receptors


47yo male presents in ED with a drug-induced hypotension. He has been taking an antiHTN drug for many months. He is not volume-depleted. You give phenylephrine at the same dose and y the route you always have. It causes no change in blood pressure. Which drug did the pt most likely take and overdose on?
A. Atenolol
B. Bethanechol
C. Prazosin
D. Propranolol
E. Guanethidine

C. Prazosin

**This is the direct opposite of phenylephrine


Pretreatment with propranolol will block which of the following?
A. Phenylephrine-induced mydriasis
B. NE-induced bradycardia
C. Phentolamine-induced tachycardia
D. Nicotinic-induced vasoconstriction
E. Pilocarpine-induced miosis

C. Phentolamine-induced tachycardia

When phentolamine acts to raise blood pressure and lower HR there are signals sent to the brain that increase sympathetic outflow causing NE to be released which then binds beta receptors on the heart increasing HR. If beta receptors are blocked prior to phentolamine administration then NE will not be able to act on the heart


Which of the following effects of epinephrine will be blocked by metoprolol but not by phentolamine?
A. Inhibition of NE release from presynaptic adrenergic terminals
B. Contraction of radial smooth muscle in the iris
C. Constriction of cutaneous vessels
D. Relaxation of bronchial SM
E. Increased renin release

E. Increased renin release


Which tissue below will respond to a catecholamine hormone that is present in the systemic circulation but not to a catecholamine NT released from postganglionic sympathetic terminals?
A. Ventricular myocytes
B. Dilator muscle of the iris
C. Arteriolar SM
D. Bronchial SM
E. SA nodal cells in the heart

D. Bronchial SM


A child has swallowed the contents of 2 bottles of a nasal decongestant whose primary ingredient is an alpha1 adrenoceptor agonist drug. The signs of an overdose that may occur in this pt include:
A. Bronchoconstriction
B. Tachycardia
C. Mydriasis
D. Vasodilation
E. Sweating

C. Mydriasis


53yo man with a 30yr Hx of asthma is being treated for HTN. Which of the following beta blockers is the most appropriate therapy for this pt?
A. Isoproterenol
B. Labetalol
C. Metoprolol
D. Propranolol
E. Timolol

C. Metoprolol


53yo woman admitted to hospital with Dx of septic shock is given emergency therapy. The tax includes an adrenergic drug that decreases total peripheral vascular resistance at lower doses and increases it at higher doses. Which of the following drugs was likely administered?
A. Phenylephrine
B. Dopamine
C. Isoproterenol
E. Albuterol

B. Dopamine


The NT agent that is released in the SA node of the heart in response to the systemic administration of alpha1-adrenoceptor agonist drug is:
A. ACh
B. Dopamine
C. Epi
D. Glutamate

A. ACh


Which of the following drugs will decrease HR in a pt with a normal heart but will have little or no effect on the HR in a cardiac transplant recipient?
A. Terbutaline
B. Isoproterenol
C. Phenylephrine
D. Propranolol

C. Phenylephrine

**There is no PNS innervation in a transplanted heart bc the nerves dont grow in there -> baroreflex is destroyed in transplanted heart