<prompt> Nitrates act by -Activate guanyl cyclase and decrease cGMPActivate guanyl cyclase and increase cGMPActivate adenyl cyclase and decrease cAMPActivate adenyl cyclase and decrease cAMP  <response>: Ans. is b i.e., ActivateGuanylcyclase and increase cGMP Mechanism of action of nitrates: Organic nitrates are rapidly denitrated enzymatically in the smooth muscle cell to release nitric oxide NO which activates cytosolic guanyl cyclase - cGMP - Vasodilatation. Veins express greater amount of the enzyme that generates NO from organic nitrates than arteries - Account for the predominant venodilatory effect. 