Nitroprusside active metabolite acts by:

Ans. B. Guanylyl cyclase* Nitrovasodilator (arteriodilator + venodilator)* Sodium nitroprusside is metabolized into nitric oxide, which activates guanylyl cyclase (directly or through release of NO) which leads to increase in cyclic GMP levels* Cyclic GMP activates protein kinase G which dephosphorylates MLCP (myosin light chain phosphorylase) and relaxes the smooth muscles of blood vessels* Vasodilatation occurs* Dose: 0.3mcg/kg/min* Onset of action: 30 sec* Therapeutic uses: Severe hypertension with acute myocardial infarction or left ventricular failure