ANS part 2: adrenergic Flashcards
alpha 1 agonists
- methoxamine
- phenylephrine
- pseudoephedrine
alpha 2 agonists
- clonidine
- alpha-methyldopa
- Methylnorepinephrine
beta 1 agonists
dobutamine
beta 2 agonist
salbutamol
beta 3 agonist
- brl37344
- mirabegron
the sympathetic NS can have different types of receptors. what are they and what do they innervate?
- adrenergic (for adrenal medulla)
- noradrenergic (smooth m, heart, glands)
- dopamine d1 (renal b.v)
- acetalcholine muscarinic (sweat glands, b.v., skeletal muscles)
adrenergic receptors are what type of receptor
GPCR
alpha 1 agonist binds to what g protein/activation?
Gq (excitation)
beta 1 and beta 2 agonist binds to what g protein/activation?
Gs (excitation)
alpha 2 binds to what g protein/activation?
Gi (inhibition)
alpha receptors have a high affinity for
E > NE»_space; isoproterenol
Non-specific antagonist for alpha receptors
phentolamine
Phenoxybenzamine
alpha 1 and 2 receptors are found
on blood vessels
binding to alpha 1 causes
vasoconstriction (and BP increases)
binding to alpha 2 causes
vasodilation
binding to alpha 1 causes excitation or inhibition of Gq?
excitation
alpha 1 receptors are found pre or post synaptic?
POST
Ag of alpha 1
methoxamine
phenylephrine
Pseudoephidrine
Antag of alpha 1 and action
prazosin, vasodilation
binding to alpha 2 causes excitation or inhibition?
inhibition of Gi
where is alpha 2 receptor found (pre or post synaptic)
PRE AND POST
Ag alpha 2 receptor and action
clonidine
Alpha methyldopa methylnorpinephrine, vasodilation
Antag of alpha 2 receptor and action
yohimbine, vasocontriction
affinity of beta receptors to agonists
isoproterenol»_space; E > NE
antagonist of beta receptors
propranolol
location of beta 1
heart
location of beta 2
respiratory system
location of beta 3
adipose tissue
antag beta 1
atenolol
effect of dobutamine
- increase HR
- increase chronotropy
effect of salbutamol
-bronchoDILATION
what is salbutamol used to treat
- asthma
- COPD
what does brl3744 do
- increase body temp
- decrease fat
what does atenolol do
- decrease HR
- decrease BP
what 2 agonists bind to both alpha and beta
-NE and E
NE has an affinity for which beta receptor
beta 1 (heart)
E has an affinity for which beta receptor
beta 1 and 2 (heart and resp. - use to treat asthma attack)
dopamine has a high affinity for which receptor
D1 and D2 (dopamine receptors)
isoproterenol has a high affinity for which receptor
beta 1 and 2
fenoldopam has a high affinity for which receptor
D1
what are the 5 endogenous adrenergic agonists
catecholamines:
- dopamine
- NE/E
- NA/A
agonist for beta 2
- albuterol
- terbutaline
- metaproternol
- ritodrine
all CA’s are synthesized from
tyrosine
order of CA molecules that are synthesized
tyrosine -> dopa -> dopamine -> norepi -> epi
dopamine is metabolised by what enzyme to form what
dopamine -> DOPAC (via MAO: monoamine oxidase)
DOPAC is metabolized by what enzyme to form what
COMT to form HVA
where is MAO found
mitochondrial surface
where is COMT found
cytoplasm
NA and A are metabolised by COMT and MAO to form what
VMA
Epi binding to alpha1 causes
vasoconstriction, increase BP, and reflex bradycardia
Epi binding to beta 1 causes
increase BP, inotropic and chronotropic
Epi binding to beta 2 causes
- bronchodilation
- coronary vasodilation (more blood to heart to help with increased BP)
what are the systemic therapeutic indications for Epi
- cardiac arrest
- hypotension/shock
- bronchospasm
- hypersensitivity reactions/anaphylactic shock
what are the topical therapeutic indications for Epi
- prolongued action of local anesthetics
2. topical hemostatic
is NE a potent agonist for alpha and beta?
only alpha and beta 1
*weak beta 2 agonist
effect of NE
- B1: increase BP
- inotropic and chronotropic
- A1: vasoconstriction
- mydriasis
what is NE used to treat
shock (with severe hypotension)
low doses of dopamine will cause
renal and splanchnic vasodilation
high doses of dopamine will cause
- vasodilation
- increased renal blood flow, diuresis, and natriuresis
why does dopamine have limited CNS access
- high polarity
- peripheral metabolism
what is dopamine used to treat
- severe hypertension
- shock (cardiogenic, renal failure)
methoxamine administered intravenously has ___(faster/slower) effects and activity compared to intramuscularly
faster and higher
what is methoxamine used to treat
- hypotensive states
- maintain BP during surgery
- paroxysmal atrial tachycardia
what effect does phenylephrine have
- lower HR
- increase stroke output
what is phenylephrine used to treat
-hypotensive state
what is pseudoephedrine used to treat
nasal decongestion
what is clonidine used to treat
hypertension
what are 3 adverse effects of clonidine
- dry mouth
- sedation
- bradycardia
what is alpha-methyldopa used to treat
hypertension
how does alpha-methyldopa work
inhibits DOPA decarboxylase, so prevents the formation of CA’s
what is dobutamine used to treat
congestive heart failure
what is salbutamol used to treat
- asthma
- chronic bronchitis
- pulmonary emphysema
what is mirabegron used to treat
overactive bladder
mechanism of action for amphetamine
- increase release of NE/DA
- inhibit MAO
- alpha agonist
CNS stimulation effects of amphetamine (D-amph)
- sleep and fatigue reversal
- stim medullary respiratory center
- suppress appetite
- psychosis
- potential for abuse and addiction
PNS stimulation effects of amphetamine (L-amph)
- increase cardiovascular
- GI (dry mouth, metallic taste, nausea, vomiting, diarrhea)
name 4 indirect adrenergic agonists
- amphetamine
- methylphenidate
- moclobemide
- phenelzine
methylphenidate is a mild CNS stimulator. what is it used to treat
- ADHD
- narcolepsy
MAO inhibitors work by
inhibiting MAO, so increase monoamines in CNS
what are MAO inhibitors used to treat
depression
name 2 indirect acting adrenergic antagonists and what they do
- alpha-methyldopa (inhibits DOPA-decarboxylase)
2. reserpine (inhibit vesicular transport)
give 2 examples of MAO inhibitors
- moclobemid (reversible)
- phenelzine (irreversible)
