Sympathomimetics Flashcards
monoamine
amino group connected to aromatic ring by two carbons
catecholamine
monoamine with catechol (benzene with two hydroxy)
biosynthesis catecholamines
L-Tyrosine
L-DOPA
Dopamine
Norepinephrine
Epinephrine
norepinephrine neurotransmission
tyrosine into ending, then to dopa
dopamine into vesicle by VMAT
dopamine to NE
calcium opens channel and vesicles fuse
NE binds adrenergic receptors
stereochemical requirements for adrenoceptor binding
catechol
amine
hydroxy
R stereochemistry
epinephrine receptor selectivity
more selective beta but alpha 1 and 2 beta 1 and 2
norepinephrine receptor selectivity
alpha 1 and 2 and beta 1 NO BETA 2
alpha 1 receptor Gq
vasocontriction
pupil dilation
ejaculation
urine inhibition
GI inhibition
alpha 2 receptor Gi
vasoconstriction
prejunctional NE inhibition
in cns decrease CV SNS input
beta 1 receptor Gs
cardiac stimulation
renin secretion
beta 2 receptor Gs
cardiac stimulation
bronchodilation
uterine relaxation
GI inhibition
vasodilation
what do alpha 1 agonists due
nasal decongestion
vascular failure in shock and tachycardia
why is phenylephrine not very effective? first pass metabolism
cant reach site, broken down in the liver
where is alpha 1 found?
smooth muscle, heart, liver
alpha 1 drug structure
imidazoline connected to carbon
where is alpha 2 found?
pre synaptically
what do alpha 2 agonists do
hypertension
pain
glaucoma
inhibit SNS activity
methyldopa is a
prodrug, not very soluble tho so methyldopate used for iv
where is beta 1 found
heart, kidney
what do beta 1 agonists do
shock, congestive heart failure
what do beta 1 antagonists do
hypertension, angina, arrhythmias, congestive heart failure
where is beta 2 found
smooth muscle
what do beta 2 agonists do
asthma, premature labor
what do beta 2 antagonists do
glaucoma
