12/9/08 Adrenergics Jacobus Systems Utcom

Front 1

name of basic of catecholamine? what is the common name?

Back 1

3.4-dihyroxyphenylethylamine
aka dopamine

Front 2

structural dif b/w epinephrine/norepinephrine and dopamine?

Back 2

NE - adds hydroxyl to beta carbon on dopamine
Epi - add methyl to amine on NE

Front 3

Describe Dopamine/NE synthesis

Back 3

Tyrosine is taken up into cell via symport with Na. Tyr->Dopa->Dopamine occurs in cytosol. Transport to vesicle via antiport with H+ (VMAT) and converted to NE.

Front 4

storage form of catecholamines?

Back 4

stored and maintained in vesicles as NE

Front 5

Inactivation of catecholamines?

Back 5

"uptake 1" - uptake via channel on presynaptic terminal, metabolized by MAO or stored back into vesicle
"uptake 2" - uptake via channel on postsynaptic membrane, metabolized by MAO and COMT to VMA (which is excreted in urine)

Front 6

inhibitor of catecholeamine "uptake 1" channel?

Back 6

cocaine and TCA (tricyclic antidepressents)

Front 7

inhibitor of vesicular storage of catecholamine?

Back 7

reserpine - depletes catecholamine stores, allows parasympathetics to dominate

Front 8

inhibitor of release of catecholamines?
what is its MOA?

Back 8

clonidine - agonist of presynaptic terminal alpha2-Rs, which inhibit axon's secretion of catecholamine by inhibiting adenylyl cyclase and hyperpolarizes cell

Front 9

list the two MAO inhibitors, and cite their differences

Back 9

Pargyline - inhibits MAO A & B
Selegiline - inhibits MAO B only
Both MAO are in CNS. MAO A is in liver, GI, placenta
MAO B is in platelets

Front 10

list the differences in beta adrenergic receptor actions

Back 10

Beta 1 - increases HR and Force; renin release
Beta 2 - SMC relax, glycogenolysis/gluconeogenesis
Beta 3 - lipolysis of adipose cells

Front 11

Specificities of catecholamines for adrenergic-Rs
Epi:
NE:
Dopamine:
Isoproterenol:

Back 11

Epi - all Rs
NE - alpha 1, alpha 2, Beta 1
Dopamine - alpha 1, beta 1
Isoproterenol - beta 1, beta 2, beta 3

Front 12

list the two indirect adrenergic agonists. what is their MOA?

Back 12

tyramine and amphetamine
they enter presyn terminal via "uptake 1" channels and stimulate NE release from its storage

Front 13

to what indirect adrenergic agonist does tolerance develop early and why?

Back 13

tyramine; occurs because it is eventually degraded to octopamine which surprisingly has ANTAGONISIC-adrenergic effects

Front 14

what drugs will inhibit tyramine's effect and why?

Back 14

drugs that either block tyramine uptake (cocaine) or block catecholaine storage (reserpine)