cGMP mechanism of muscle relaxation

[ChessMaster3000]

So Rx/UW describes the Nitric oxide mechanism of smooth muscle relaxation as increasing cGMP, which then increases calcium efflux from smooth muscle cells resulting in relaxation. FA14 p. 418 describes it as cGMP activating myosin-light chain phosphatase, which would dephosphorylate myosin light chain and decrease its affinity for actin. Which one is correct, or are they both partially correct?

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[Donald Juan]

Both
NO stimulates guanylate cyclase activity --> cGMP increases and activates PK-G

PK-G activates myosin-light chain phosphatase, impairing myosin-actin binding
It also activates Ca pumps on the SR, lowering Ca
And it inhibits L-type Ca channels, preventing Ca influx from outside the cell