pharmacology: adrenergic drugs Flashcards
(48 cards)
where are alpha 1 receptors? effects?
- radial muscle eye (contraction = mydriasis without cyclopegia@)
- arterioles (contraction = increased TPR = increased diastolic pressure = increased afterload)
- veins (contraction = increased venous return = increased preload = increased systolic BP)
- bladder trigone and sphincter and prostatic urethra (contraction = urinary retention)
- male sex organs (vas deferens = ejaculation)
- liver (increased glycogenolysis)
- kidney (decreased renin release - safety valve - don’t want too much increase in BP)
where are alpha 2 receptors? effects?
- prejunctional nerve terminals (decreased transmitter release and NE synthesis
- platelets (aggregation)
- pancrease (decrease insulin secretion)
what type of receptor is alpha 1?
Gq = increased calcium
what type of receptor is alpha 2?
Gi couples = decreased cAMP
where are B1 receptors? effects?
- heart: oppose muscarinic 2
SA node - (increased HR (positive chronotropy))
AV node (increased conduction velocity (positive dromotrophy))
atrial and ventricular muscle (increase force of contraction (positive inotropy), conduction velocity, CO and oxygen consumption)
his-purkinje (increase automaticity and conduction velocity - kidney: increase renin release (complementary effect with rest of Beta 1)
what type of receptor is beta 1?
Gs coupled: increase cAMP
what type of receptor is beta 2?
Gs coupled = increased cAMP
MOSTLY NOT INNERVATED - NE CAN’T REACH!! EPI!!!!!!!
where are beta 2 receptors? effects?
- blood vessels (all) - (vasodilation = decreased TPR = decreased diastolic pressure = decreased afterload)
- uterus (relaxation - prevent premature labor)
- bronchioles (dilation - relaxation)
- skeletal muscle (increased glycogenolysis - contractility (tremor))
- liver (increased glycogenolysis, gluconeogenesis, lipolysis)
- pancrease (increase insulin secretion - in order to allow glucose uptake)
which receptors are most sensitive?
beta receptors! when drugs have both effects, beta responses are dominant at low doses!! alpha at higher doses
where are D1 receptors located? effects?
renal, mesenteric, coronary vasculature (vasodilation - in kidney increased RBF, increased GR, increased Na+ secretion)
fenoldopam - mechanism and clinical
D1 agonist - used for severe hypertension (causes vasodilation)
what type of receptor is D1?
Gs coupled - increased adenylyl cyclase = increased cAMP
how is potential reflex bradycardia blocked with alpha 1 agonists?
M2 blockers
what is the direct acting alpha 1 agonist? clinical use?
phenylephrine - nasal decongestant and ophthalmologic use (mydriasis without cycloplegia)
phenylephrine effect on blood pressure
increase mean blood pressure via vasoconstriction of both arterioles and veins - no change in pulse pressure
what are the alpha 2 agonists? clinical use?
clonidine and methyldopa - mild to moderate hypertension (decrease sympathetic outflow)
what are the beta agonists? clinical use?
isoproterenol (B1=B2) - bronchospasm, heart block, bradyarrhythmias
dobutamine (B1>B2) - CHF (increased CO)
isoproterenol side effects
flushing, angina, arrhythmias
beta 1 agonist effects
increased HR, increased SV, increased CO, increased pulse pressure (d/t increase in contractility)
beta 2 agonist effects
decreased TPR, decreased BP
what are the selective beta 2 agonists? clinical uses?
salmeterol (prophylaxis asthma), albuterol (asthma), terbutaline (premature labor)
NE effect on BP
can NEVER lower BP because it has NO B2 activity
low dose epinephrine effects
B1: increased HR, increased SV, increased CO, increased PP
B2: decreased TPR and decreased BP
medium dose epinephrine effects
B1: increased HR, increased SV, increased CO, increased PP
B2: decreased TYPR, decreased BP
A1 effects!!!: increased TPR, increased BP (antagonism causes no change in BP)
