Endogenous/Drug effects on receptor Flashcards
Norepinephrine has a low affinity/efficacy at what two receptors?
B2 & B3
EPI binds to what receptor causing bronchodilation?
B2
At low concentrations, epinephrine binds to what receptor?
What is the effect?
B2
vasodilation
At high concentrations, epinephrine binds to what receptor?
What is the effect?
A1
vasoconstriction
List 3 bronchodilators?
Epi
isoproterenol
albuterol
What can block NET? What is the result?
Cocaine and TCA(amitriptyline)
increased available Norepi
Methylxanthines (caffeine)
bronchodilation
Phenylephrine cause increase myocardial contractility by 2-3x WHY?
post junctional A1 receptors on heart
more prominent in failure or ischemia due to receptor upregulation
Sympathomimetic drugs such as ephedrine do what?
act using endogenous NT
Sympathomimetic drugs act primarily on what receptors
A1 and B1
Epi (agonist) primarily stimulates what receptors?
B1,2,3
Norepi stimulates_____, but minimal______ receptor activity?
B1
B2
Dopamine is a ____receptor agonist?
Beta
Stimulation of SNS causes 80% release of____from adrenal medulla.
Epi
Catecholamines are?
sympathetic amines with hydroxy substitutions 3 and 4 of benzene ring
Cocaine does what?
blocks reuptake of NE
Tyramine is
from fermented food, contraindicated with mao inhibitor
Tyramine, amphetamine, ephedrine cause what?
increase available nor epi, reuptake inhibition
Epinephrine in large doses may cause
PVC, tachycardia, fibrillation
The negative SE of EPI may exacerbated in
MI and anesthetic agents
In the presence of a beta blocker EPI will act as
vasoconstriction
EPI causes increased coronary blood flow via
metabolic adenosine
EPI via A1 causes high vasoconstriction where?
skin vasculature
Epinephrine indirectly increase blood pressure why?
Positive inotropic and chronotropic
Place in order affinity for A1&A2
Isoprotenrol
epi
norepi
epi
norepi
isoproterenol
epi>=NE»i
Place in order affinity for B1
Isoprotenrol
epi
norepi
B1 Isoprotenrol epi norepi i>epi=NE
Place in order affinity for B2&B3
Isoprotenrol
epi
norepi
Isoprotenrol
epi
norepi
i>=epi»NE
Dobutamine would be a good choice for what patient?
Short term cardiac decompensation states(post CT surg, acute MI, CHF
In severe CHF dobutamine would be a shit choice. Why?
down regulation of b adrenergic receptors would decrease its effectiveness.
Dobutamine facilitates AV conduction and may cause
ventricular ectopy.
Dobutamine predominantly simulates which receptor
B1
Dobutamine is more prominent inotrope or chronotrope?
inotrope
Pheonochromocytoma will cause an increase of ______release by the _____of _______%?
norepi
adrenal medulla
97%
A low dose of epi 2-10mcg will cause
B3 lipolysis
Epi can cause an increase in this electrolyte______. Why?
Potassium
Increased Na-K pump action
Ephedrine may cause this adverse action______ if taken with ________.
HTN crisis
moa inhibitors
Isoproterenol and epinephrine are
equally effective in stimulating
release of free fatty acids and in
energy production
The duration of action of isoproterenol is somewhat longer than
epi
Inotropic
force of contraction
Chronotropic
rate