adrenergic system Flashcards
what’s the substrate for synthesizing Nora?
tyrosine
where is tyrosine obtained?
dietary protein
whats the rate limiting step of synthesizing Nora?
tyrosine being hydroxylated to dihydroxyphenylaline ( DOPA) by tyorsine hydroxylase
what converts DOPA into dopamine?
dopa decarboxylase
whats the role of gunaethidine?
blocks release of NA
what is the main presynaptic receptor that NA binds to?
alpha 2
which enzyme metabolizes NA in the synaptic space?
COMT
which enzyme metabolizes NA in the neuron?
MAO
what inhibits reuptake of NA ?
cocaine
alpha receptors affinity ranking ( highest to lowest)
epinephrine
Norepinephrine
isoproterenol
alpha receptor subtypes
1 and 2
all the adrenergic receptors are what?
G protein coupled receptors
beta receptors subtypes
1 2 and 3
whats the predominant receptor in smooth muscles?
alpha (1 and 2)
whats the predominant receptor in the heart?
beta 1
what receptors stimulate cAMP?
alpha 1 and all beta
what receptors inhibit cAMP?
alpha 2
what happens if alpha 1 adrenoreceptors are activated?
vasoconstriction
relaxation of GI SM
hepatic glycogenolysis
what happens if alpha 2 adrenoreceptors are activated?
inhibit Nora release
inhibit insulin release
what happens if beta 1 adrenoreceptors are activated?
increase cardiac rate and force
release if renin from kidneys
what happens if beta 2 adrenoreceptors are activated?
bronchodilator
vasodilation
relaxation of uterus
what happens if beta 3 adrenoreceptors are activated?
lipolysis
what are the two main groups of adrenergic agonists?
catecholamines and non catecholamines
whats a catecholamine made up of ?
catechol G anf amine G
whats a catechol G ?
benzene ring that has hydroxyl Gs on 2 adjacent carbons
what is the amine component of catecholamines?
ethylamine
what differentiates catechol amines from noncatecholamines?
lack of catechol group
can’t be metabolized by COMT
what are sympathomimetic drugs?
produce same effect as stimulating SNS
b1 receptors act on
heart and kidney
increase rate force automaticity
b2 receptors act on
smooth muscle ( relaxation)
b3 receptors
adipose tissue ( increase lipolysis)
if patient is taking MAO inhibitors then a tyramine containing diet can cause what?
vasopressor effects ( hypertensive crisis)
adrenergic blockers are highly effective in
treatment of cardiac disease
physiological effects of adrenergic blockers
lower bp and heart rate
dilate bvs
adrenergic blockers aka
sympatholytic agents
selective alpa 1 adrenergic blockers inhibit
catecholamines ability to constrict bvs
beta 1 blockers are
cardioselective
alpha blockers bind to receptors on
vascular smooth muscle
drugs that inhibit alpha 1
reduce blood pressure
alpha one is recommended as _______ not mono therapy ( alone) of hypertension
adjunctive
alpha adrenergic blockers side effects
orthostatic hypotension
nasal congestion
reflex tachycardia
beta blockers cause
decrease hr and contractility of heart
alpha adrenergic blockers side effects
orthostatic hypotension
nasal congestion
reflex tachycardia
beta blockers cause
decrease hr and contractility of heart
