Autonomic Sympathetic Drugs: Sympathomimetics Flashcards
Alpha 1 is coupled to
Gq
Alpha 2 is coupled to
Gi
Beta 1 is coupled to
Gs
Beta 2 is coupled to
Gs
Alpha 1 receptor coupled to Gq causes
alpha-1 receptor coupled to Gq → IP3-DAG cascade → increased intracellular calcium (smooth muscle cell)
alpha-1 activation causes
- increased peripheral arterial resistance (vasoconstriction at small arteries, arterioles, precapillary sphincters)
- increased mean arterial pressure (MAP)
- increased venous return (venoconstriction)
- at pupillary dilator muscle causes mydriasis (pupillary dilation)
- urethral sphincter and prostatic smooth muscle contraction
- Urinary retention
alpha-1 activation at pupillary dilator muscle causes
mydriasis (pupillary dilation)
alpha-1 activation at _______ ________ _____ causes mydriasis (pupillary dilation)
pupillary dilator muscle
alpha-2 agonists are
alpha-2 agonists are sympatholytics (act centrally to decrease sympathetic tone)
alpha-2 receptor coupled to Gi
alpha-2 receptor coupled to Gi → decreased cAMP
presynaptic alpha-2 receptors cause
presynaptic alpha-2 receptors cause inhibition of neurotransmitter release
alpha-2 activation at pancreatic islet cells
decreases insulin release
alpha-2 activation inhibits
lipolysis and release of fatty acids
alpha-2-activation
- alpha-2 activation at pancreatic islet cells decreases insulin release
- alpha-2 activation inhibits lipolysis and release of fatty acids
- activation of alpha-2 at ciliary body decreases aqueous humor production
activation of alpha-2 at ciliary body
decreases aqueous humor production
activation of alpha-2 at ______ ________ decreases aqueous humor production
ciliary body
brimonidine is
brimonidine is an alpha-2 agonist used to treat chronic open angle glaucoma (decreases aqueous humor production)
beta receptor agonists increase
cyclic AMP (cAMP)
beta-1 receptors are found on
cardiac myocytes (including SA and AV nodes)
beta-1 activation causes
beta-1 activation causes increased cyclic AMP → increased intracellular calcium
beta-1 activation increases
- heart rate (SA node)
- cardiac contractility
- renin release (JGA cells)
beta-1 activation results in increased
cardiac output
beta-2 activation leads to
beta-2 activation leads to bronchoDILATION (increased cyclic AMP → activates PKA)
beta-2 activation causes
beta-2 activation causes coronary and skeletal muscle vasoDILATION → decreases systemic vascular resistance (SVR)
beta-2 activation stimulates
lipolysis and release of free fatty acids
beta-2 receptor activation at the liver promotes
gluconeogenesis
beta-2 activation at pancreatic islet cells
beta-2 activation at pancreatic islet cells stimulates insulin release → moves glucose into cells
beta-2 activation can cause _______ due to increased insulin activity
hypokalemia
beta-2 activation can cause hypokalemia due to
increased insulin activity
beta-2 activation at ciliary body increases
aqueous humor production
Alpha 1 agonist
- phenylephrine
phenylephrine treats
nasal congestion (alpha-1 mediated vasoconstriction)
phenylephrine causes
- mydriasis (activates alpha-1 at pupillary dilator muscle)
- reflex bradycardia (response to alpha-1 increase in MAP)
Phenylephrine increases
- MAP (alpha-1 increase in SVR)
- systolic pressure (alpha-1 arteriolar constriction)
- diastolic pressure (alpha-1 venous constriction)
NORepinephrine ________ agonist
alpha>beta1 agonist
norepinephrine has some
norepinephrine has some beta-1 activity (primarily an ALPHA AGONIST)
Norepinephrine increases
- MAP (alpha-1 increase in SVR)
- systolic pressure (alpha-1 arteriolar constriction)
- diastolic pressure (alpha-1 venous constriction)
- cardiac contractility (activates beta-1)
norepinephrine causes
norepinephrine causes reflex bradycardia (response to alpha-1 increase in MAP)
In Septic Shock
septic shock (phenylephrine and norepinephrine increase SVR and venous return to treat distributive/hypovolemic shock)
DOBUtamine
beta-1>beta-2 agonist
dobutamine is primarily a
beta-1 agonist
dobutamine increases
- heart rate, contractility, and cardiac output (beta-1 effects)
- PULSE PRESSURE, difference between systolic and diastolic (beta-1 increase in contractility)
- systolic pressure (beta-1 increase in CO)
dobutamine has some
beta-2 activity (primarily a BETA-1 AGONIST)
dobutamine causes
dobutamine causes vasodilation → decreases SVR (effects mild due to minimal beta-2 activity)
Dobutamine can decrease
diastolic pressure (beta-2 arteriolar dilation)
______ increases PULSE PRESSURE, difference between systolic and diastolic (beta-1 increase in contractility)
- norepinephrine
- dobutamine
- Isoproterenol
- epinephrine
dobutamine can be used in
cardiogenic shock
dobutamine increases contractility and CO to treat
cardiogenic shock
isoproterenol
beta-1=beta-2 agonist
isoproterenol increases
heart rate and contractility (beta-1 effects)
isoproterenol causes
isoproterenol causes vasodilation → decreases SVR (beta-2 effects)
isoproterenol decreases
- DIAstolic pressure (beta-2 vasodilation and decreased SVR)
- MAP (beta-2 decrease in SVR)
Isoproterenol decreases diastolic pressure
- beta-2 arteriolar dilation
2. beta-2 vasodilation and decreased SVR
beta-2 agonists relax
uterine smooth muscle
prevents premature labor (beta-2 relaxes the uterus)
- Terbutaline
2. Ritodrine
beta-2 agonists used for bronchodilation have _____ suffix
“-rol”
beta-2 agonists used for bronchodilation have “-rol” suffix
- albuterol
- formoterol
- salmeterol
EPInephrine
beta>alpha agonist
at LOW doses, epinephrine’s ______ effects predominate
at LOW doses, epinephrine’s BETA AGONIST effects predominate
epinephrine causes
epinephrine causes bronchodilation (beta-2 effects)
at LOW doses, epinephrine decreases
at LOW doses, epinephrine decreases DIAstolic pressure (beta-2 vasodilation and decreased SVR)
Epinephrine increased
epinephrine increased heart rate and cardiac contractility (beta-1 effects)
at HIGH doses, epinephrine’s ______ effects predominate
at HIGH doses, epinephrine’s ALPHA AGONIST effects predominate
Epinephrine increases MAP
- MAP (alpha-1 increase in SVR)
2. systolic pressure (alpha-1 arteriolar constriction)
Epinephrine can decrease
diastolic pressure (beta-2 arteriolar dilation)
epinephrine increases SVR and bronchodilates to treat
anaphylactic shock