Augmented sympathetic nervous function in young subjects with borderline hypertension

Area of Science:

• Cardiovascular Physiology
• Neuroendocrinology

Background:

• Borderline hypertension is characterized by blood pressure levels between normal and established hypertension.
• The underlying mechanisms of blood pressure elevation in borderline hypertension require further elucidation.
• Sympathetic nervous system (SNS) activity is a key regulator of blood pressure.

Purpose of the Study:

• To investigate the role of sympathetic nervous system activity in the mechanism of blood pressure elevation in patients with borderline hypertension.
• To compare SNS activity in young and middle-aged men with borderline hypertension.

Main Methods:

• Measurement of plasma catecholamine (CA) levels.
• Assessment of cardiovascular responsiveness to exogenous catecholamines.
• Measurement of cerebrospinal fluid (CSF) noradrenaline levels.
• Evaluation of CA levels following hypertonic saline loading.

Main Results:

• Elevated plasma catecholamine levels were observed in young men with borderline hypertension compared to controls.
• Cardiovascular responsiveness to exogenous catecholamines was not augmented in young men with borderline hypertension.
• Increased cerebrospinal fluid noradrenaline levels correlated positively with plasma noradrenaline and blood pressure in young men with borderline hypertension.
• Plasma and urinary catecholamine levels remained unchanged after hypertonic saline loading in young men with borderline hypertension.

Conclusions:

• Increased central and peripheral sympathetic nervous system activity is a significant mechanism contributing to blood pressure elevation in young individuals with borderline hypertension.
• Age appears to be a factor in the manifestation of elevated catecholamine levels in borderline hypertension.