The working mechanism of adrenergic β receptor

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as I know the second messenger of adrenergic β receptor is the "Gs system"which cause adenylate cyclase activated, cAMP up
my question is that:
β1 receptor on the heart has the effect of muscle contraction
but
β2 receptor on the vessel of skeletal muscle will cause vessel dilation(by relaxing smooth muscle),and bronchodilation(smooth muscle relaxing)

both β receptor are working through the Gs but β1 receptor will make the muscle contraction and β2 receptor will cause the muscle relaxing, what's the mechanism makes the different effect on muscle?

Originally Posted by hpw

as I know the second messenger of adrenergic β receptor is the "Gs system"which cause adenylate cyclase activated, cAMP up
my question is that:
β1 receptor on the heart has the effect of muscle contraction
but
β2 receptor on the vessel of skeletal muscle will cause vessel dilation(by relaxing smooth muscle),and bronchodilation(smooth muscle relaxing)

both β receptor are working through the Gs but β1 receptor will make the muscle contraction and β2 receptor will cause the muscle relaxing, what's the mechanism makes the different effect on muscle?

Think about the cell type that is expressing the receptors. Not all muscle is created equal and activation of PKA does different things in different places.

would you please tell me the detail difference of the PKA mechanism?

Originally Posted by hpw

would you please tell me the detail difference of the PKA mechanism?

Have you ever heard of google or wikipedia?

ya, I have google about it, but I can't find the answer.

http://www.cvphysiology.com/Blood%20Pressure/BP026.htm
http://www.cvpharmacology.com/cardio...ta-agonist.htm
http://www.cvphysiology.com/Blood%20Pressure/BP011a.htm

Dr. Klabunde's site is well done. He also has a really good book.

http://www.amazon.com/dp/1451113846/...2Ftextbook.htm

It's interesting that we are taught all this reductive pharmacological theory, yet no one has ever given a convincing explanation of why beta blockers work in heart failure.

To ucladoc2b:thank you for your answering, it helps me a lot
To Asp:I was curiosity to that issue too, would you have good explain for it?