Endothelial dysfunction in essential hypertension is characterized by which of the following?

Endothelial dysfunction in essential hypertension is characterized by which of the following?

• A. Reduced nitric oxide and increased endothelin lead to higher vascular tone.
• B. Increased nitric oxide and reduced endothelin lead to higher vascular tone.
• C. No change in nitric oxide or endothelin.
• D. Only endothelin changes with no NO involvement.

Answer: (A)

Endothelial control of vascular tone hinges on a balance between nitric oxide, which relaxes smooth muscle, and endothelin-1, which constricts it. In essential hypertension, this balance shifts toward constriction: nitric oxide bioavailability is reduced due to impaired production and increased scavenging by reactive oxygen species, while endothelin-1 levels or activity are increased. The result is a net rise in vascular tone and a diminished ability of vessels to dilate in response to stimuli. This combination explains why endothelial dysfunction in essential hypertension is characterized by lower NO and higher endothelin, leading to sustained vasoconstriction and higher blood pressure.

Endothelial control of vascular tone hinges on a balance between nitric oxide, which relaxes smooth muscle, and endothelin-1, which constricts it. In essential hypertension, this balance shifts toward constriction: nitric oxide bioavailability is reduced due to impaired production and increased scavenging by reactive oxygen species, while endothelin-1 levels or activity are increased. The result is a net rise in vascular tone and a diminished ability of vessels to dilate in response to stimuli. This combination explains why endothelial dysfunction in essential hypertension is characterized by lower NO and higher endothelin, leading to sustained vasoconstriction and higher blood pressure.