What is the mechanism of action of nitroprusside in treating hypertensive crisis?

Nitroprusside is a potent vasodilator used in the management of hypertensive crises, and its primary mechanism of action is to directly relax vascular smooth muscle. When nitroprusside is administered, it is metabolized to release nitric oxide (NO), which activates guanylate cyclase within vascular smooth muscle cells. This leads to increased levels of cyclic guanosine monophosphate (cGMP), resulting in the relaxation of these muscle cells. The dilation of blood vessels reduces systemic vascular resistance and lowers blood pressure rapidly and effectively.

This mechanism is particularly beneficial in hypertensive emergencies, where it is crucial to lower blood pressure quickly to prevent complications such as organ damage. The effects of nitroprusside can be adjusted by changing the infusion rate, allowing for precise control of blood pressure during acute situations. Other options provided do not relate to the distinct and effective action of nitroprusside in treating hypertension.