Unit 4: Adrenergic Agonists Flashcards by Michelle Herman

Stimulation of the adrenal glands causes secretion of…

epinephrine and norepinephrine

How well did you know this?

Not at all

Perfectly

The drugs that cause effects similar to epinephrine or norepinephrine are called _____ or ____

adrenomimetics

sympathomimetics

How well did you know this?

Not at all

Perfectly

The adrenoreceptors are …

alpha
beta
dopamine

How well did you know this?

Not at all

Perfectly

define SELECTIVITY

drug binds preferentially to one subset of adrenoreceptors

How well did you know this?

Not at all

Perfectly

define SPECIFICITY

near absolute selectivity; also, some drugs interact with more classes of receptors at higher doses/concentration

How well did you know this?

Not at all

Perfectly

list 3 terms that describe the desensitization that happens when a cell or tissue is exposed to an agonist over time, and that cell/tissue becomes less responsive to further stimulation from the agent

tolerance
refractoriness
tachyphylaxis

How well did you know this?

Not at all

Perfectly

major action that occurs with stimulation of alpha 1 receptors

smooth muscle contraction

How well did you know this?

Not at all

Perfectly

alpha 1 receptors are located…

eye
hair shaft
prostate
heart
vascular smooth muscle

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 1 RECEPTORS causes _____ in the EYE

contraction of muscle –> dilates pupil

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 1 RECEPTORS causes ____ in the HAIR

erection

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 1 RECEPTORS causes ____ in the PROSTATE

contraction

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 1 RECEPTORS causes ____ in the HEART

increase in contractile force

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 1 RECEPTORS causes ____ in the VASCULAR SMOOTH MUSCLE

contraction –> arterial and venous vasoconstriction

How well did you know this?

Not at all

Perfectly

What does PHENYLEPHRINE do?

pure alpha agonist –> increases peripheral arterial resistance and venous capacitance –> dose-dependent increase in BP –> baroreceptor-mediated increase in vagal tone –> decrease in heart rate

How well did you know this?

Not at all

Perfectly

locations of alpha 2 receptors

postsynaptic CNS neurons
platelets
adrenergic and cholinergic nerve terminals
some vascular smooth muscle
fat cells

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 2 RECEPTORS causes ____ in the PLATELETS

aggregation

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 2 RECEPTORS causes ____ in the ADRENERGIC and CHOLINERGIC NERVE TERMINALS

inhibition of transmitter release

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 2 RECEPTORS causes ____ in the VASCULAR SMOOTH MUSCLE

contraction

How well did you know this?

Not at all

Perfectly

stimulation of ALPHA 2 RECEPTORS causes ____ in the FAT CELLS

inhibits lipolysis

How well did you know this?

Not at all

Perfectly

SYSTEMIC administration of alpha 2 agonists do what

inhibit sympathetic tone and decrease BP

How well did you know this?

Not at all

Perfectly

What is clonidine and what is it used for?

alpha 2 agonist, used to treat HTN

How well did you know this?

Not at all

Perfectly

Where are the beta 1 receptors located?

heart

juxtaglomerular cells

How well did you know this?

Not at all

Perfectly

Where are the beta 2 receptors located?

smooth muscle of respiratory system, uterus, vascular system
skeletal muscle
human liver

Where are the beta 3 receptors located?

bladder

fat cells

What does stimulation of Beta 1 receptors cause?

heart --> increased rate and contractile force | juxtaglomerular cells --> increased renin release

What does stimulation of Beta 2 receptors cause?

smooth muscle of respiratory system, uterus, vascular system --> muscle relaxation skeletal muscle --> promotes uptake of potassium human liver --> activates glycogenolysis

What does stimulation of Beta 3 receptors cause?

bladder --> relaxes detrusor muscle | fat cells --> activates lipolysis

What does ISOPROTERENOL do?

nonselective beta agonist that activates both beta 1 and beta 2 increases cardiac output due to increased contractility and direct SA node activation which increases heart rate

Where are the dobutamine receptors located?

D1: smooth muscle D2: nerve endings

What does stimulation of Dopamine 1 receptors cause?

smooth muscle: dilates renal blood vessels

What does stimulation of Dopamine 2 receptors cause?

nerve endings: modulates neurotransmitter release

What does DOPAMINE do and what is it used for?

D1 receptor activation --> causes vasodilation; improves perfusion

What does DOPAMINE do in low vs high doses?

LOW: decreased peripheral resistance HIGH: vasoconstriction due to activation of vascular alpha receptors

How do we deal with the vasoconstriction of DOPAMINE in high doses?

add DOBUTAMINE

What does DOBUTAMINE do?

beta 1 agonist | increase heart rate, contractility, and cardiac output to maintain renal perfusion

What effect does a beta 2 agonist have on the lungs?

bronchodilation to treat asthma

What effect does an alpha 2 agonist have on the eyes?

constricts "constrictor muscle" to improve flow of aqueous humor and decrease intraocular pressure for treatment of glaucoma

What effect does an alpha 1 agonist have on the genitourinary system?

contracts bladder base, urethral sphincter, and prostate to treat urinary incontinence

What effect does a beta agonist have on glucose, insulin, and metabolism?

increased lipolysis --> increased free fatty acids in the blood increased insulin secretion from the pancreas

What effect does an alpha 2 agonist have on the pancreas?

decreased insulin secretion

What effect does alpha 1 agonism have on smooth muscle?

contraction of blood vessels, eye, bladder, prostate, uterus

What effect does alpha 1 agonism have on the liver?

glycogenolysis

What effect does alpha 1 agonism have on the salivary glands?

profuse secretion

What effect does a beta 1 agonist have?

increased heart rate and force as well as increased automaticity

What effect does a beta 2 agonist have?

smooth muscle relaxation

What effect does a beta 3 agonist have?

increased lipolysis

What do the indirect sympathomimetics do?

act by releasing previously-selected norephinephrine

What are some of the uses of indirect sympathomimetics?

ephedra: weight loss phenylpropanolamine: appetite suppressant AMPHETAMINES: CNS stimulants used to treat ADHD and narcolepsy

What is the risk of a sympathomimetic?

widespread and nonspecific effects which can impact the cardiovascular system

Most important effects to remember for sympathomimetics

alpha 1: most vascular smooth muscle; agonists CONTRACT beta 1: heart; agonists INCREASE RATE beta 2: respiratory and uterine smooth muscle; agonists RELAX

Which drugs activate both alpha and beta receptors?

EPINEPHRINE and NOREPINEPHRINE

Why is epinephrine and not norepinephrine used for the treatment of bronchospasm?

because epinephrine has a low affinity for beta 2, so is not as good at relaxing bronchial smooth muscle

What does EPINEPHRINE do?

primarily affects heart via beta 1 receptors; causes increase in heart rate, stroke volume, and cardiac output

What does NOREPINEPHRINE do?

vasoconstriction --> increases blood pressure --> reflex increase in parasympathetic output to heart, which slows the heart rate (happens DESPITE agonism of beta 1)

Effect of EPINEPHRINE on blood pressure

DOSE DEPENDENT