Study Set Content:
Inner part of the adrenal gland, which secretes mainly epinephrine but also small amounts of norepinephrine.
(1) Adrenal Medulla
Drugs that affect receptors stimulated by norepinephrine or epinephrine.
Adrenergic drugs
Drugs that mimic or stimulate the adrenergic nervous system or the actions of epinephrine or norepinephrine
(3) Sympathomimetics
Drugs or endogenous catecholamines that activates a and/or B receptors. These drugs are also known as sympathomimetics.
(4) Adrenergic Agonist
they directly interact with and activate adrenoceptors (eg. norepinephrine. and epinephrine)
(5) Direct agonists
their actions are dependent on their ability to enhance the actions of endogenous catecholamines.
(6) Indirect agonists
MAJOR A AND ß DIRECT-ACTING
• EPINEPHRINE
• NOREPINEPHRINE
• DOPAMINE
These indirect agents may have either of two different mechanisms:
(1) they may (blank) stored catecholamines from the adrenergic nerve ending(eg, the mechanism of action of tyramine),
displace
(2) they may (blank) of released norepinephrine either by
➢(blank) of catecholamines already released (eg, the mechanism of action of cocaine and tricyclic antidepressants)
decrease the clearance, inhibiting reuptake
preventing the (blank) of norepinephrine(monoamine oxidase and catechol-O-methyltransferase inhibitors).
enzymatic metabolism
Some drugs have both
direct and indirect actions
Ex. of indirect-acting adrenergic agonists:
• amphetamine
• tyramine
Ex. Of two mixed (direct and indirect) agonists:
• Ephedrine
• Metaraminol
Ex. Of direct-acting adrenergic drugs
• Clonidine
• Dopamine
• Epinephrine
• Norepinephrine
• Isoproterenol
ultimately cause activation of adrenoceptors, leading to some or all of the characteristic effects of endogenous catecholamines.
Both types of sympathomimetics, direct and indirect,
The pharmacologic effects of direct agonists depend on the (blank), their relative (blank) for adrenoreceptor subtypes, and the relative (blank) of these receptor subtypes in target tissues.
route of administration, affinity, expression
The pharmacologic effects of____ sympathomimetics are greater under conditions of increased sympathetic activity and norepinephrine storage and release
indirect
MOLECULAR PHARMACOLOGY UNDERLYING THE ACTIONS OF SYMPATHOMIMETIC DRUGS
• The effects of catecholamines are mediated by
cell-surface receptors.
Adrenoceptors are typical
G protein-coupled receptors (GPCRs).
The receptor protein has an extracellular ____, traverses the membrane seven times (transmembrane domains) forming three extracellular and three intracellular loops, and has an intracellular C terminus.
N-terminus
