ANS pharmacology Flashcards
clonidine
a2 receptor agonist = stimulates inihbitory autoreceptors= decrease NE release = hence decreased PVR, HR and BP
(main anti-HT action is via CNS)
pseudoephedrine
indirect agonist = increases NE
given intranasally = local vasoconstriction = nasal decongestant
pheochromocytoma
a tumor secreting excessive nor(epinephrine)
prazosin
a1 receptor antagonist = reduces BP
competitive reversible
decreases peripheral vasoconstriction
decreases peripheral arterial resistance
phenoxybenzamine
a1 and a2 antagnosist
irreversible
binds covalently = good for treating pheochromocytoma
phenylephrine
a1 agonist = increases BP
increases peripheral vasoconstriction
increases peripheral arterial resistance
propranolol
prototype B blocker, blocking b1 and b2 receptors
Contraindications of propranolol
compensated cardiac failure (sympathetic drive important to keep <3 working)
asthma (impedes bronchodilator caused by sympathetic input)
physical fatigue (even in normal subject)
propranolol therapeutic uses
HT
Angina pectoris
cardiac arryhthmia
albuterol
short acting B2 agonist
aka salbulatomol, Ventolin
relaxes bronchial smooth muscle = breathing!
M1 receptors
brain, postganglionic neurone
M2 receptors
autoreceptors and heart – what is stimulated by ACh released by the vagus nerve in the SA node to reduce HR
M3 receptors
airways, exocrine glands
cocaine
blocks reuptake of NE in the synapse; excessive NE can increase BP and cause stroke
A1 receptors
vascular smooth muscle
A2 receptors
Autoreceptros, inhibit NE release
B1 receptors
adrenergic receptor in heart
B2 receptors
adrenergic receptors in lungs
what are the opposing effects of the sympathetic system on PVR
vasoconstriction in skin and viscera via a1 receptors responding to NE and Epi
vasodilation in skeletal muscle via B2 receptors responding to Epi only
epinephrine (receptors)
FIGHT OR FLIGHT
stimulates all 4
vasoconstrictor (a1)
vasodilator (b2)
cardiac stimulant (b1)
norepinephrine receptors
AT REST
stimulates all but LITTLE B2
vasoconstrictor (a1)
[vasodilator (b2)]** does not vasodilator in skeletal muscles, only EPI does that
cardiac stimulant (b1)
