Epi: The Prototype Endogenous Catecholamine

Question 1

What receptors does Epi hit?

Answer 1

All 4 (Alpha 1, Alpha 2, Beta 1 and Beta 2)

Question 2

Where is Epi the most potent activator?

Answer 2

Alpha receptors

Question 3

Why does Epi have little CNS effect?

Answer 3

It is very poorly lipid soluble.

Question 4

What is the onset of SQ epi?

IV?

Answer 4

5-10minutes

1-2 minutes

Question 5

What is the standard bolus dose of Epi for resus? What about if the patient is not in CV collapse?

Answer 5

10mcg/kg IV

Can start with 2-8mcg/kg

Question 6

If given a single bolus of Epi how quickly will the CV effects dissipate?

Answer 6

1-5minutes

Question 7

At drips flowing at 1-2mcg/min what receptors are we hitting more than the others?

Answer 7

Beta 2

Question 8

At drips flowing at 4-5mcg/min what receptors are we hitting more than the others?

Answer 8

Beta 1

Question 9

At drips flowing at 10-20mcg/minute what receptors are we hitting hard?

Answer 9

Both Alpha and Beta

Question 10

Which adrenoreceptors does epi stimulate?

Answer 10

All of them.

Question 11

What is the result of Epi hitting alpha1 receptors on the CV system?

Answer 11

Vasoconstriction

Increased BP, CVP and Cardiac Work

Question 12

What is the result of Epi hitting alpha2 receptors on the CV system?

Answer 12

Decreased blood pressure (negative feedback)

Question 13

What is the impact on the CV system when Epi hits the B1 receptors?

Answer 13

Increased contractility, HR, CO and BP

Question 14

What is the impact on the CV system when Epi hits the B2 receptors?

Answer 14

Peripheral vasodilation

decreased BP[-= (my kitten drew this smiley face walking across my keyboard so I’m leaving it)

Question 15

With moderate doses of epi what happens to SBP, DBP and MAP?

Answer 15

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.

Question 16

What happens to the skin, mucosa, hepatic and renal vasculature with epi?

Answer 16

constricted through alpha 1

Question 17

What happens to the skeletal muscle with epi?

Answer 17

dilated with B2

Question 18

At clinically relevent doses of Epi we see minimal vasoconstriction of arterioles in what three places?

Answer 18

1. Cerebral vasculature
2. Coronary vasculature
3. Pulmonary vasculature

Question 19

What other effect does Epi tend to have on cerebral vasculature?

Answer 19

Increased cerebral blood flow in general (even with normal BP secondary to redistribution of blood flow)

Question 20

How does Epi accommodate for far vision?

Answer 20

Through interaction with alpha 1 receptors- mydriasis (dilation)

Question 21

How does Epi affect regulation of IOP?

Answer 21

Alpha 1 and 2 increase humoral outflow

Beta 1 increases production of aqueous humor.

Question 22

What three effects does Epi have on the respiratory system? Make sure to name the receptors responsible.

Answer 22

1. Dilates smooth muscle of bronchial tree- B2
2. Decreased release of vasoactive mediators (histamine) in bronchial vasculature- B2
3. Reduce mucosal secretion-decongestion- A1

Question 23

What three GI effects do we see with Epi? Make sure to name the receptors responsible. What dramatic effect do we see here?

Answer 23

1. Decreased digestive secretions- A2
2. Decreased peristalsis- A, B2- direct smooth muscle relaxation
3. Decreased splanchnic blood flow- A1- blood flow drastically reduced even if BP is relatively normal!

Question 24

What two major effect does Epi have on renal vasculature?

Answer 24

1. Renal blood flow is drastically reduced even if BP is relatively normal- A1
2. Increase of renin release- B1

Question 25

What two effects do we see in the bladder from Epi?

Answer 25

1. Contraction of urethral sphincter- A1

2. Decrease urinary output- B2

Question 26

What effect does Epi have on the erectile tissue?

Answer 26

1. Facilitates ejaculation- A1

Question 27

What effect does Epi have on the uterus?

Answer 27

1. Inhibits labor- B2

Question 28

What three metabolic effects do we see with Epi?

Answer 28

1. Increased liver glycogenolysis- B2
2. Increased adipose tissue lipolysis- B3
3. Inhibition of insulin release- A2