How does Beta 2 agonist cause smooth muscle relaxation?

[What the pho]

I know in the heart beta 1 increases ca influx, increase ca atpase, and removes inhibition of phospholambam (spelling not sure). But how does beta 2 cause relaxation, esp beta 2 given to pregnant women to prevent uterine contractions? Thanks ahead of time.

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[Mossjoh]

Its a G-protein mediated event through inhibition of myosin light chain kinase.

 

[uclacrewdude]

kinda makes sense:
in cardiac myocytes ^ contractility & ^ hr = ^ CO
in smooth myocytes \/ contraction = \/ resistance = ^ flow