EX 3 Cholinergic Flashcards
What is the baroreceptor reflex?
feedback loop between the spinal cord and brain
what does the baroreceptor reflex do?
regulates BP and maintaines homeostasis
- watch for BP changes and sends a message to the brain
what is an agonist
molecules that activate reptor
what is an antagonist
prevents or blocks receptoractivation
these mediate responses to epinephrine and norepinephrine
adrenergic drugs
what are the Alpha1 adrenergic agonists/ which drugs act directly on the Alpha 1 receptor
Phenylephrine
epinephrine
norepinephrine
Where does the Alpha 1 receptor work on and what happens when activated
(BEVAPP)
Bladder - contraction (stops voiding0
Eye - contraction of iris
Veins - constriction
Areterioles - vasocnstrictions
Penis - ejacultation
Prostate capsule - contraction
what is phenylephrine used for and what receptor does it act on
nasal decongestion, Alpha 1
what is epinephrine used for and what receptor does it act on,
homeostasis
adjunct to local anaesthesia
Alpha 1,2 and Beta 1,2
what is mydriasis
contraction of iris muscle + pupil dilation
what is norepinephrine used for and what receptor does it act on
(rarely) BP elevation, Alpha 1, Alpha2, and Beta 1
Adv Effects of Alpha1 agonists
HTN (can be severe with IV admin)
Bradycardia
Tissue necrosis (if an IV extravasates)
Where does the alpha 2 receptor work on and what happens when activated
Presynaptic nerve terminals - inhibits transmitter release
Where does the Beta 1 receptor work on and what happens when activated
Heart - increased rate, contraction strength, conduction velocity over AV node
Kidney - release of renin
Where does the Beta 2 receptor work on and what happens when activated
(SKLUBA)
Skeletal muscle - enhanced contraction
Kidney - dilation of kidney blood vessels
Liver - glycogenolysis
Uterus - relaxation
Bronchi - dilation
Arterioles - Dilation
Where does the Dopamine receptor work on and what happens when activated
Kidney - dilation of kidney blood vessels
Alpha 1 therapeutic uses?
mostly based on vasoconstriction
Beta 1 therapeutic uses?
on the heart
- heart failure (dopamine, isoproterenol)
- shock (dopamine, isoproterenol)
- Av heart blocks (epinephrine)
- restarting after cardiac arrest (epinephrine)
Adverse effects of Beta 1 activation
tachycardia, dyshythmias, angina pectoris
Beta 2 therapeutic uses?
Lungs (and uterus)
asthma - albuterol
- prefer meds that are selective for B2 receptors only
- delays of preterm labor
Adverse effects of beta 2 activation
- hyperglycemia (typically in pt w/DM
- muscle tremors
Dopamine receptor activation
dopamine is the receptor and the drug
considerations for dopamine receptor activation
Given IV, weight based, very short T1/2
Dopamine receptor activation in low doses
- dilation of renal blood vessels
- improves GFR and urine output, maintains kidney function
Dopamine receptor activation in high doses
- Beta 1 and Alpha 1 effects; vasoconstriction, increased BP & HR, improved cardiac output
- used for hemodynamic support: shock, advanced heart failure
Adverse effects of dopamine receptor activation seen in high doses
Dysrhythmias/tachycardia (activation of B1)
Angina pectoris (activation of B1)
Tissue Necrosis if IV infusion extravasates (vasoconstriction)
Epinephrine receptor activation
activates all alpha and beta receptors= broad range of effects and clinical uses
Epinephrine A1 receptor activation
- delay absorption of local anesthetic, control bleeding, raise blood pressure, induce mydriasis during ophthalmologic procedure
Epinephrine B1 receptor activation
reverse AV heart blokc, restore rhythm during cardia arrest
Epinephrine B2 receptor activation
Bronchodilation (not preferred drug)
- treatment of anaphylaxis/shock
Pharmokinetics of epinephrine
absorption: topically or by injection
metabolism: in liver and intestine very short T1/2
Adverse effects of epinephrine
HTN crisis,
Dysrhythmias/tachycardia
angina pectoris
necrosis if IV infusion extravasates
hyperglycemia
interacts with A1 and beta blockers
A1 Blocker protype
prazosin (selective)
Therapeutic uses of prazosin (A1 blocker)
- essential HTN
- renal stones
- Raynaud’s Disease
- Reversal of overdose/toxicity of A1 agonists