Epi: The Prototype Endogenous Catecholamine Flashcards
What receptors does Epi hit?
All 4 (Alpha 1, Alpha 2, Beta 1 and Beta 2)
Where is Epi the most potent activator?
Alpha receptors
Why does Epi have little CNS effect?
It is very poorly lipid soluble.
What is the onset of SQ epi?
IV?
5-10minutes
1-2 minutes
What is the standard bolus dose of Epi for resus? What about if the patient is not in CV collapse?
10mcg/kg IV
Can start with 2-8mcg/kg
If given a single bolus of Epi how quickly will the CV effects dissipate?
1-5minutes
At drips flowing at 1-2mcg/min what receptors are we hitting more than the others?
Beta 2
At drips flowing at 4-5mcg/min what receptors are we hitting more than the others?
Beta 1
At drips flowing at 10-20mcg/minute what receptors are we hitting hard?
Both Alpha and Beta
Which adrenoreceptors does epi stimulate?
All of them.
What is the result of Epi hitting alpha1 receptors on the CV system?
Vasoconstriction
Increased BP, CVP and Cardiac Work
What is the result of Epi hitting alpha2 receptors on the CV system?
Decreased blood pressure (negative feedback)
What is the impact on the CV system when Epi hits the B1 receptors?
Increased contractility, HR, CO and BP
What is the impact on the CV system when Epi hits the B2 receptors?
Peripheral vasodilation
decreased BP[-= (my kitten drew this smiley face walking across my keyboard so I’m leaving it)
With moderate doses of epi what happens to SBP, DBP and MAP?
SBP increases because of alpha 1 and beta 1 receptors.
DBP tends to decrease because of B2 receptors
Map tends to stay the same.
So we see a widening of our pulse pressure.
What happens to the skin, mucosa, hepatic and renal vasculature with epi?
constricted through alpha 1
What happens to the skeletal muscle with epi?
dilated with B2
At clinically relevent doses of Epi we see minimal vasoconstriction of arterioles in what three places?
- Cerebral vasculature
- Coronary vasculature
- Pulmonary vasculature
What other effect does Epi tend to have on cerebral vasculature?
Increased cerebral blood flow in general (even with normal BP secondary to redistribution of blood flow)
How does Epi accommodate for far vision?
Through interaction with alpha 1 receptors- mydriasis (dilation)
How does Epi affect regulation of IOP?
Alpha 1 and 2 increase humoral outflow
Beta 1 increases production of aqueous humor.
What three effects does Epi have on the respiratory system? Make sure to name the receptors responsible.
- Dilates smooth muscle of bronchial tree- B2
- Decreased release of vasoactive mediators (histamine) in bronchial vasculature- B2
- Reduce mucosal secretion-decongestion- A1
What three GI effects do we see with Epi? Make sure to name the receptors responsible. What dramatic effect do we see here?
- Decreased digestive secretions- A2
- Decreased peristalsis- A, B2- direct smooth muscle relaxation
- Decreased splanchnic blood flow- A1- blood flow drastically reduced even if BP is relatively normal!
What two major effect does Epi have on renal vasculature?
- Renal blood flow is drastically reduced even if BP is relatively normal- A1
- Increase of renin release- B1
What two effects do we see in the bladder from Epi?
- Contraction of urethral sphincter- A1
2. Decrease urinary output- B2
What effect does Epi have on the erectile tissue?
- Facilitates ejaculation- A1
What effect does Epi have on the uterus?
- Inhibits labor- B2
What three metabolic effects do we see with Epi?
- Increased liver glycogenolysis- B2
- Increased adipose tissue lipolysis- B3
- Inhibition of insulin release- A2
