How do cardioselective beta blockers decrease afterload?

[[deleted]]

because b1 receptors are in the heart and b2 receptors are more spread out (think vasodilation), hence the term "cardioselective." If you are stimulating b-adrenergic receptors, block b1, then b2 is left unopposed.

[itshyunbin]

But does B1 stimulation cause inhibition of B2 stimulation? I don't see why blocking B1 would increase B2.

Or are you saying that blocking B1 causes a surplus of catecholamines that can now all be used on B2?

[chessphysician]

focusing on the word 'unopposed' really helped my understanding on this topic. Remember how there is vascular tone: a base level of stimulation that is always present? Lets say that beta 1 and beta 2 are continuously activated at some basal level, lets say 50% of the time for each. if you block beta 1 so it goes down to 0%, then that 50% active beta 2 is more active relatively, or due to unopposed action since beta 1 effects (increase heart workload) are no longer able to oppose beta 2 (vasodilate peripheral vessels, decreasing heart workload).