Why does adrenaline have a small effect on ABP??

[StrongBeliever]

In my book, it says,

Adrenaline has less effect [I think they're comparing it to noradrenaline] on ABP due to vasoconstriction and vasodilatation of skeletal muscle arterioles and so TPR is slightly affected.
It affects SBP while DBP is slightly decreased.
Pulse pressure is augmented but MAP is not or little affected.

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[BigRedBeta]

Read up on the difference between alpha and beta adrenergic receptors, their function and location, and the relative strength of response for epi/norepi to each type of receptor. You'll find your answer there.

 

[cellsaver]

In my book, it says,

Adrenaline has less effect [I think they're comparing it to noradrenaline] on ABP due to vasoconstriction and vasodilatation of skeletal muscle arterioles and so TPR is slightly affected.
It affects SBP while DBP is slightly decreased.
Pulse pressure is augmented but MAP is not or little affected.

You did not state which book you are using but if you want to learn this stuff you will need to avail yourself to more than one book. This material is not easy and it doesn't come by passive learning. That was the case for me particularly when it came to secondary messengers.

low dose Epinephrine: modest alpha 1 stimulation but greater Beta 1 / Beta 2 stimulation.
+ B1 = increase cardiac contractility, stroke volume, cardiac output
+ B2 = vasodilation ==> decrease TPR and BP

high dose Epinephrine: alpha 1 stimulation is greater than B1/B2 stimulation.
+ a1 = vasoconstriction dominates over B2 vasodilation at high dose Epinephrine. hence increase in TPR and BP while still having sustained cardiac contractility from B1. This is why Epi is used for Cardiac Arrest

I did not benefit much from a basic physiology textbook like Costanzo when it came to cardiology. I had to use a more specific book to understand the cardiovascular system. Pathophysiology of Heart Disease by Lilly was excellent. I learned most of my cardiovascular content from Lilly's book Attached figure is from Lilly's book.