Autonomics: Sympathomimetics Flashcards
What are the G proteins associated with each Sympathetic receptor?
a1 = Gq a2 = Gi b1 = Gs b2 = Gs
(QISS)
What does activation of a1 receptors lead to?
- increased peripheral arterial resistance
- increased mean arterial pressure (MAP)
- increased venous return (venoconstriction)
- mydriases due to activation of the pupillary dilator muscle
- urethral sphincter and prostatic smooth muscle contraction
- urinary retention
Which drugs are sympatholytics? What does that mean?
Alpha 2 agonists are sympatholytics (act centrally to decrease sympathetic tone)
What is the MOA of a2 receptors?
decrease cAMP, and cause inhibition of neurotransmitter release
What is the effect of a2 activation on the pancreas?
a2 activation at pancreatic islet cells decreases insulin release
(rolled up “welcome inside” mat)
What is the effect of a2 receptors on fat metabolism?
a2 activation inhibits lipolysis and release of fatty acids
dude stopping the roasting of a pig
What is the effect of a2 receptors on the eyes?
activation of a2 at the ciliary body decreases aqueous humor production
What is Brimonidine?
Brimonidine is an alpha 2 agonist used to treat chronic open angle glaucoma by decreasing aqueous humor production
What is the effect of b1 receptors in the heart?
b1 receptors found on cardiac myocytes cause increase cAMP, leading to increased intracellular calcium, which increases contractility and accelerates the heart. Also increases cardiac ouput
What is the effect of b1 receptors in the kidney?
b1 activation increases renin release (JGA cells)
open rain umbrella, rainin
What is the effect of b2 activation on the lungs?
b2 activation leads to bronchodilation
camper taking a big breath
Why does b2 activation decrease SVR?
b2 activation causes coronary and skeletal muscle vasodilation, leading to a decreased systemic vascular resistance
What is the effect of b2 receptors on fat metabolism?
b2 activation expressed on human fat cells stimulates lipolysis and release of free fatty acids
What are some other effects of b2 activation?
- promotes gluconeogenesis at the liver
- increased insulin release
- hypokalemia
- increased aqueous humor production at ciliary body
What is the MOA of phenylephrine?
a1 agonist, causes smooth muscle activation
flannel guy
