Adrenergic Drugs Flashcards
(64 cards)
why do many clinical applications and toxicities associated with adrenergic drugs involve the cardiovascular system
- it is an SNS dominant system involved in rapid regulation of blood pressure
what makes up blood pressure
cardiac output x vascular time (PVR)
what categories can adrenergic drugs be divided into
sympathomimetics (direct or indirect)
adrenergic antagonists
what are the different types of sympathomimetics (adrenergic drugs)
direct acting: activate receptors directly
indirect acting: increase level of NE at synapse, therefore increase activity at multiple receptor sub-types
what do structural differences in sympathomimetic drugs determine
- presence of -OH groups increase potency and susceptibility to COMT
- additional methyl group on the a-carbon makes it resistant to MAO
- addition of a methyl group at the N-terminal end alters receptor affinity
what is the difference in structure between NE and EP
EP has an extra methyl group therefore changes which receptors it binds
how is receptor affinity altered by the size of groups added at the N-terminal end of a sympathomimetic
- large groups = increased B-receptor activity
- small groups = increased a-receptor activity
which direct acting agonists have mixed affinity
epinephrine: a1 = a2, B1 = B2
norepinephrine: a1 = a2, B1»_space; B2
which direct acting agonists have affinity for a-receptors
phenylephrine: a1»_space; a2
clonidine: a2»_space; a1
which direct acting agonists have affinity for B-receptors
dobutamine: B1 > B2
Isoproterenol: B1 = B2
albuterol: B2»_space; B1
what are the direct acting adrenergic agonists
norepinephrine
epinephrine
phenylephrine
clonidine
dobutamine
isoproterenol
albuterol
what are the indirect acting adrenergic agonists
tyramine
amphetamine
cocaine
what drugs are adrenergic antagonists
prazosin
yohimbine
metoprolol
propranolol
butoxamine
where are a1 receptors found
bladder
stomach
blood vessels (organs and skin)
eye
sphincters
where are B1 receptors found
heart
adrenal medulla
eye?
where are B2 receptors found
eye
blood vessels (skeletal muscle)
bronchi
stomach
small intestine
bladder
uterus (genitals)
what is the difference between NE and EP secretion
- NE is released from nerve terminals at target tissue
- EP is secreted from the adrenal medulla and circulates via blood to tissues
what mechanism do adrenoreceptors (a and B) uswe to send signals
GPCR messenger systems
what effect do a1 receptors have in GPCR systems
increase IP3 and DAG production - stimulatory effect
what effect do a2 receptors have in GPCR systems
decrease cAMP production - inhibitory effects
what effect do all beta receptors (B1, B2, B3) have in GPCR systems
increase cAMP production - stimulatory effect
what effects do different adrenergic receptors have in the eye
contraction of dilator/radial muscle (dilate pupil - mydriasis) = a1
decrease aqueous humor = a1, a2
increase aqueous humor = B1, B2
what effects do adrenergic receptors have in the heart
B1 in the heart = increase rate and force of contraction
what effects do adrenergic receptos have in blood vessels
a1 in BV of organs and skin = vasoconstriction
B2 in BV of skeletal muscles = vasodilation