Sympathetic / Adrenergic Flashcards
Andrenergic transmission steps
Synthesis Uptake into vesicles Release Binding to Receptor Removal
Rate limiting step in the synthesis
Hydroxylation of tyrosine
Inhibitors of synthesis
Metyrosine and
Carbidopa
Inhibits transport into vesicle
Reserpine
Facilitates release of NE
Calcium
Block release of NE
Guanethedine
Bertylium
Causes release of NE
M - methamphetamine
E - Ephedrine
T - tyramine
A - amphetamine
Removal
Methylaed by
COMT
catechol o-methyltransferase
COMT destroys
Catecholamines
Epi, NE, dopamine
Removal
Oxidized by
MAO
monoamine oxidase
MAO destroys
Monoamines
NE, dopamine, serotonin
Inhibits reuptake
Cocaine
TCA (tricyclic antidepressants)
Urine metabolites
Vanillylmandelic acid
Metanephrine
Normethanephrine
Alpha 1
B - blood vessel - vasoconstriction P - pili arrector muscle - constriction S - spinchter P - constriction G - glands
Alpha 2
Preganglionic - central
Postganglionic - peripheral
Beta islet cells of pancreas
Beta 1
Heart
Kidney
Beta 2
B - bronchus U - uterus B - blood vessel S - contraction P - pancreas; stimulates INSULIN RELEASE M - metabolism
Beta 3
Adipose tissue
Dopamine 1
BV of Renal Mesenteric Coronary Cerebral vascular Beds VASODILATION
Dopamine 2
CNS
STIMULATION
Sub-groups of DIRECT ADRENERGIC AGONISTS
Catecholamines
Non-catecholamines
Unique feature of catecholamines
3,4-dihydroxybenzene group
Catecholamines
Metabolized by COMT and MAO
ineffective orally
Polar
Do not readily penetrate the CNS
Has the HIGHEST potency in activeting the alpha and beta receptors
Catecholamines
Non-catecholamines
LONGER HALF-LIVES
increased lipid solubility, thus greater access to CNS
[SUBSTITUTION ON THE BENZENE RING]
Absence of ONE OR BOTH -OH GRP IN THE CATECHOL
Without other substitutions
Reduce potency
Increase BA after PO
prolongs duration of action
Increase distribution to the CNS
[SUBSTITUTION ON THE ALPHA CARBON]
Blocks oxidation by MAO
prolongs action
Ephedrine, amphetamine
Other name for alpha methyl cmpds
Phenylisopropylamine
[SUBSTITUTION ON THE BETA CARBON]
Substitution of a hydroxyl group of the beta carbon
Decreases activity with the CNS bec of decreased lipid solubility
Enhances agonist activity for both alpha and beta receptors
Directly bind to adrenergic receptors
Direct acting sympathomimetics