What is the mechanism leading to reflex sympathetic response when nitroprusside is administered without certain medications?

When nitroprusside is administered, it acts as a potent vasodilator, leading to a decrease in systemic vascular resistance. This rapid vasodilation can result in a significant drop in blood pressure (hypotension). The body perceives this drop in blood pressure and triggers a reflex sympathetic response as a compensatory mechanism.

The sympathetic nervous system responds to the hypotension by increasing heart rate and contractility, alongside peripheral vasoconstriction to restore blood pressure to an acceptable level. Therefore, the reflex sympathetic response is directly linked to the vasodilation and resultant hypotension caused by nitroprusside, making vasodilation with hypotension the correct choice.

This understanding highlights the physiological processes of the body responding to changes in blood pressure, particularly in the context of managing acute hypertension or during surgical settings, where nitroprusside may be used to rapidly reduce blood pressure.