CID Autonomic Pharm Flashcards
Binding to muscarinic receptors cause what?
Contraction of smooth muscle
What would a muscarinic receptor antagonist do?
Relax the target organ
A man is walking and his HR and CO increase–> BP. What is responsible for this?
NE binding to B1 receptors -
B1 receptors are located on the AV nod.
Increase the rate and strength of contraction
Alpha 1 receptors do what?
Increase BP by causing vasoconstriction, controlling the smooth muscle around the vasculature.
Increase CO is proportional to an increase in what?
PRESSURE
A1 agonists do what?
What is an example?
Increase mean BP
decrease HR
Ex. Phenylephrine
A1 agonists (phenylephrine) increases BP, but decrease HR.
How does this affect sympathetics?
-Increase baroreceptor reflex
-increase parasympathetic response
- Decrease sympathetic response
What does histamine do?
Decreases BP.
-Decreases baroreceptor firing
-Decrease parasympathetics
-Increase sympathetics
NET and DAT inhibitors do what?
Give an example
Increase NE/DA in the cleft.
Ex. Cocaine
What would a AChE inhibitor do?
Increase amount of ACh
-Cause ACh to bind to muscarinic receptors
-Decrease in HR
VMAT inhibitors
Reduce the release of cathecholamines because it blocks them from entering the vesicles.
Pt comes in with SOB, wheezing, tachycardia, RR or 32/min. How can we treat?
- Beta 2 receptor agonist- relaxes smooth muscle in the lungs
- mAChR antagonist- relaxes smooth muscle (give if the pt does not respond to muscarinic agonists)
John is a given a drug that will increase the force of contraction (+ ionotropy) and decrease the HR (negative chronotropy) of cardiac contraction.
What is the target of the drug?
Na+/K+ ATPase blockers
(Cardiac glycosides)
How do cardiac glycosides work?
Cardiac glycosides, like digoxin, will block Na+/K+ pumps, causing a buildup of Na+ inside the cell. To prevent a build up, we activate the NCX receptors, which allow 3 Na+ to leave and 1 Ca2+ to enter.
Thus, it causes an increase in intracellular Ca2+.
This will increase the force of contraction, but decrease our heart rate.
B1 receptors
____ force of contraction
_____ heart rate
Increase the force of contraction (+ ionotropic effect)- more blood is delivered to the tissue
increase the heart rate (+ chronotropic effect)
M2 and M3
___ force of contraction
____ heart rate
Decrease force of contraction (negative ionotropic effect)
Decrease heart rate (negative chronotropic effect)
In heart failure; we see a decrease CO.
How does our body respond
- Decrease firing of baroreceptors
- -decrease parasympathetic activity
- -increase sympathetic activity (increase force, increase HR, increase preload, increase afterload)
- Decrease a renal blood flow will cause renin to be released.
- -angiotensinogen–> angiotensin 2
- Adrenal medulla- release of aldosterone
- Posterior pituitary- release of ADH (vasopressin
- Hypothalamus- increase thirst
- Vasoconstriction
- Increases preload, afterload and remodlings
- This can cause EDEMA
How can we decrease the force and rate of cardiac contraction?
- Muscarinic agonist
- B1 receptor antagonist
2 yo old had an accidental overdose on antihistamines.
high temp
pupils are fixed and dilated
HR is 160 bpm
Cutaneous vasodilation
What receptors are involved?
Muscarinic receptor antagonist =
Decreases parasympathetic tone
increases sympathetic
-Patient cannot sweat anymore and gets hot, causing an increase in temperature. To cool off, the bodies compensatory response is to vasodilate.
2 yo old had an accidental overdose on antihistamines.
high temp
pupils are fixed and dilated
HR is 160 bpm
Cutaneous vasodilation
What receptors can we stimilate to corrext sx? W what type of drug?
-mAChR via a AChE inhibitor
