Chapter 10: Adrenergic Agents Flashcards by AFD Alvarez

modulation of the sympathetic nervous system can be done in 2 ways: ___ and ___

interacting with adrenergic receptors (direct); modulating amount of NE released into synapses (indirect)

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t/f alpa ardrenergic receptors have multiple isoforms within each subtype

true

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where are a1 receptors located?

vascular smooth muscle, prostate, heart

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stimulation of a1 receptors has what physiologic response?

contraction

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what is the mechanism of a1 receptors?

couple to gq protein, increase ca, increase contraction

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what is the locatio of the a2 receptors?

cns

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stimulation of a2 receptors has what physiologic response?

decreased NT release, indirect effect on decreasing heart contraction

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what is the mechanism for A2 receptors?

couple to Gi protein, decrease cAMP levels

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congestion in allergic rhinitis is caused by

swelling surrounding vascular tissue by immune cells infiltrating the area in response to histamine

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stimulating a1 receptors activates the ____ coupled protein, increasing ___ and ___ which increaing intracelluar ___ leading to the smooth muscle contraction

Gq; Dag anf IP3; ca

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what is the effect of A1 receptor activation on the sinuses?

constriction of blood vessels, reducing leakiness and infiltration of immune cellls to the area, resulting in congection

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phenylephrine is a ____ commonly found in over the counter decongestants like tylenol sinus and is also found in combination products like cold and flu remedies

A1 receptor agonist

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the actions of phenylephrine to reduce congestion may have adverse effects in patients with ____

hypertension

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blocking the A1 receptor reduces ____ of the prostate and facilitates ____ of the bladder

smooth muscle contraction; voiding

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A1A is found in the ___ smooth muscle

prostate

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A1B is found in the ___ smooth muscle

vascular

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list 2 examples of A1A receptor antagonists

prazosin

2. tamsulosin

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what receptors does prazosin act on?

A1A and A1b adrenergic receptors

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what is an off target effect of prazosin?

lowering blood pressure

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tamslulosin is more selective for what type of receptor?

A1A adrenergic receptor (no effect on BP)

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excessive use of local phenylephrine in nasal spray can cause ___ of the A1 adrenergic receptors

downregulation

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if congestion gets worse as a result of down regulation of the A1 adrenergic receptor, will adding more agonist (decongestant drug) help?

NO!

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presynaptically in the CNS, stimulation of A2 receptors ___ the release of NT

reduces

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A2 receptors are often called ____ receptors

auto

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the function of autoreceptors is to reduce ___ by limiting the amount of ___ that can be released in the synapse

over-stimulation; NT

A2 receptors are expressed on the ___ neurons

presynaptic

stimulation of the autoreceptors reduces excitability of the ___ neuron

presynaptic

explain the inhibitory process that follows the activation of an A2 receptor

Gi coupled signalling cascade is activated, inhibiting adenyl cyclase and reducing cAMP and reduced opeining of Ca channels whcih prevents the release of NE vessicles

clonidine is an example of an A2 adrenergic receptor ___

agonist

what is the function of clonidine?

stimulates A2 receptors to reduce the amount of released of NE

what is the therapeutic use of clondidine? In what patients does it work best in?

lower bp ; those not responding to other antihypertensives

which of the beta receptors are more widespread in the body?

B1 receptors are located in the ___

heart

both B receptors cause the increase in production of ___

cAMP

both B receptors are coupled to what G protein?

stimulation of B 1 receptors causes

increased heart rate and contractility

what the effect of lung B2 stimulation?

bronchodilation

what is the effect of smooth muscle B2 stimulation?

relaxes

what is the effect of liver b2 stimulation?

glycogenolysis

NE, E and dobutamine are examples of B1 ____

agonists

dobutamine is a ___ B1 agonist that can be used in emergency situations to increase ___

synthetic; cardiac output

in cardiac cells, the increae in cAMP activates ___

PKA

what is the effect of PKA on cardiac cells?

phosphorylate voltage-gated ca channels, which increases the amount of Ca that enters the cells during membrane depolarization, therefore greater cardiac output

epinephrine causes an increase in the mean ____ bp

arterial

blocking B1 with propranolol prevents the actions on epinephrine in the ___ but not in the ___

cardiac muscle; blood vessels

competitive antagonists of B adrenergic receptors are typically called ___

beta blockers

the clinical use of propranolol has declined and selective b blockers like ___ are on the rise

metroprolol

metoprolol and other selective B blockers are preferred because they ...

act in cardiac tissue and have fewer unintended effects

propranolol is a ___ beta blocker

non-selective

metoprolol is a ___ B blocker

selective

____ was one of the first clinically available B blockers for hypertension

propranolol

propranolol is very ____ , has a high ___ and can enter the ___

lipophillic, Vd; CNS

metoprolol has ___ agonist activity

inverse

topical b blockers in the form of eyedrops are used for treatment of ___ . Is this a common course of treatment for this condition?

glaucoma ; no but it used to be very popular

what are the 2 effects of using topical b blockers in glaucoma?

1. decreases aq humour production | 2. decreases IOP

give an example of topical beta blocker used in the treatment of glaucome

timolol

which beta receptor is suggested to be the path to lowering IOP in the use of timolol?

timolol is a ___ B blocker

non-selective

in the lungs, modulation of B2 receptors is important to treating conditions such as ___ and ___

asthma and COPD

B2 are expressed extensively in the ____

lungs

endogenously, ___ has a higher affinity for B2 receptors than ___

E; NE

when the symapthetic system is activated, much of the response in the lungs is due to what NT?

epinephrine

____ is used to treat bronchoconstriction in anaphylactic shock

epinephrine

epinephrine has actions at A1 and B1 receptors, so to decrease bronchocondtriction, there are also significant cardiovascular effecst, why is this not too big of an issue?

half life of epinephrine is short, so effects are not prolonged

what is salbutamol?

synthetic B2 receptor agonist that is inhaled to cause bronchodilation

where does salbutamol act?

locally in the lungs

the action of salbutamol occurs ____

rapidly

when is salbutamol administered?

at onset of symptoms in patients with asthma

B2 agonists such as salbutamol are typically called ____ medications for the treatment of asthma

rescue

pseudophedrine is an example of a ___ adrenergic receptor agonist

mixed

pseudoephedrine can be found in some OTC ____ products, but has been controllled due to it being a starting material for making ___

cold and decongestant; methamphetamine (crystal meth_

the primary therapeutic target of pseudoephedrine is ___ receptors to cause ___

A1; vasoconstriction

pseudoephedrine also targets ___ receptors, which increases cardiac output

beta

the effect of pseudoephedrine on B receptors can be problematic for patients with ___

hypertension

t/f blocking both A and B receptors reduces BP more than if only one was activated alone

true

Carvediol is an ____ of B1, B2 and a1 receptrs

antagonist

what is the primary action of carvediol?

lower bp

carvediol binds reversibly or irreversibly?

reversibly

what is the order of receptor affinity from highest to lowest in carvediol ?

B1, A1, B2

blocking B2 may worsen they symptoms of __ and ___

asthma and COPD

blocking A1 may worsen the symptoms of ___

orthostatic hypotension

what patients should not take carvediol?

patients with asthma, COPD and hypotension

___-like drugs are structurally similar to catecholamines, thus are good substrates for catecholamine transporters

amphetamine

what is the action of amphetamine/

enters presynaptic cell ny NET, taken into the NE vessicles by VMAT and then displaces NE from the vessicle and accumulate in the cytoplasm until it is passively released into the synapse

are action potentials required for amphetamine to cause release of NE?

adderall is the amphetamine available as an RX for patients with

ADHD

speed is an example of an ___

amphetamine

when acting on the CNS, amphetamine in most people casues a ___

rush or a high

___ and ____ block the NET transporter, preventing NE reuptake into presynaptic neuron

cocaine and atomoxetine

therapeutically, atomoxetine is another Rx option for

ADHD