Section 2b Adrenergic Agonists Flashcards
what amino acid is DOPA made from?
Tyrosine
What part of the catecholamine biosynthesis happens in the cytoplasm?
Tyrosine –> DOPA –> Dopamine
Where does the majority (~90%) of catecholamines (NE) come from?
Presynaptic (re)uptake via NET
what blocks catecholamine synthesis?
methyltyrosine
what blocks catecholamine storage?
reserpine via VMAT - release empty vesicles
what increases catecholamine release?
tyramine, amphetamine (indirect action)
what blocks catechol. release?
guanethidine
what blocks chatechol. (re) uptake presynaptically?
cocaine, tricyclic antidepressants via NET (indirect action)
what blocks chatechol. metabolism?
MAO inhibitors
Where are VMAT 1 and 2 found?
1 = peripheral 2 = CNS
What is a NET selective blocker?
Atomoxetine - treatment of ADHD
what has a mixed (direct and indirect) adrenergic agonist action?
ephedrine
What is the preference of Epi vs NE for B1 and B2?
B1 - Epi=NE
B2 - Epi>NE
What is the preference of Epi, NE, and Iso for a receptor?
Epi > NE > Iso
What is the preference of Epi, NE, and Iso for B receptor?
Iso > Epi > NE
What is the receptor preference for phenylephrine?
a1 > a2»_space;> B
What is the receptor preference for Clonidine?
a2 > a1»_space;> B
What is the receptor preference for NE and Epi?
NE: a1 = a2; B1»_space; B2
Epi: a1 = a2; B1 = B2
What is the receptor preference for Dobutamine? Isoproterenol? Terbutaline/Albuterol?
Dobutamine: B1 > B2»_space; a
Isoproterenol: B1 = B2»_space;a
Terbutaline/Albuterol: B2»_space;> B1»_space;» a
What is the receptor preference for Fenoldopam?
D1»_space;> D2
What are the 4 major effects (in tissues) that a1 do?
- vascular smooth muscle = vasoconstriction (increased blood pressure)
- Pupillary dilator (radial) = contraction (pupil dilation)
- Urinary bladder (sphincter) = contraction
- Prostate = contraction
What are the 2 major effects (in tissues) that a2 do?
- adrenergic nerve terminals = inhibit transmitter release
2. pancreatic = decrease insulin secretion
What are the 2 major effects (in tissues) that B1 do?
- heart = increase rate and force of contraction
2. renal jux. cells = increase renin secretion
What are the 6 major effects (in tissues) that B2 do?
- respiratory smooth muscle = bronchodilation
- uterine smooth muscle = relaxation (prego)
- vascular skeletal muscle = vasodilation
- urinary bladder (detrusor wall) = relaxation
- liver = glycogenolysis, gluconeogenesis
- pancreas = increase insulin secretion
Major effects (in tissues) that B3 does?
adipose tissue = lipolysis
What senses high blood pressure and responds with an increase in vagal tone which decreases heart rate? where is it located and how does it work?
baroreflex sensors/mechanism in the neck – it is fast acting with the release of ACh in the sinoatrial node which decreases BP
what do NE, Isoproterenol, and Epi do to systolic pressure?
and of these 3 which decreases pulse rate?
Epi = decreases it
NE = increases it (decrease pulse rate)
Isoproterenol IV = markedly decreases it
What are adrenergic receptors and effects in teh respiratory tract? (2)
- bronchodilation (B2)
2. decongestant (a1)
What are the adrenergic receptors and effects in the genitourinary tract? (3)
- urinary continence (a1A, B2)
- ejaculation (a1)
- uterine relaxation in pregnant women near term (B2)
What are the adrenergic receptors and effects in the eye? (3)
- mydriasis (dilation) (a)
- increased outflow of aqueous humor (a)
- decreased production of aqueous humor (B antagonists)
What do B’s increase? (3)
lipolysis, insulin secretion, and renin secretion
What do a2 decrease? (3)
lipolysis, insulin secretion, and renin secretion
