Evaluating sympathetic activity in human hypertension.
OBJECTIVE
To review the use of plasma norepinephrine to evaluate sympathetic activity in humans, and to discuss the improvement in assessment of human sympathetic activity brought about by the norepinephrine spillover method and by microneurography.


METHODS
Literature survey.


RESULTS
These methods have limitations, and an accurate assessment of sympathetic cardiovascular control should not be limited to an investigation of sympathetic nerve firing or norepinephrine secretion but include cardiac and vascular responses. These responses can be assessed by traditional pharmacological means (for example, a reduction in vascular resistance induced by alpha-adrenergic blockade) or by a variety of approaches aimed at examining sympathetic cardiovascular modulation in a more integrated fashion, such as the recently developed power spectrum analysis of blood pressure and heart rate.


CONCLUSIONS
The sensitivity and specificity of all these methods is still under investigation, but in almost every case an increase in sympathetic cardiovascular influence has been reported to occur in hypertension, indicating that sympathetic activation has a pathogenic effect on this condition.
Mancia
G
G
Cattedra di Medicina Interna, Ospedale S. Gerardo Monza, Milan, Italy.
Grassi
G
G
Parati
G
G
Daffonchio
A
A
D001794:Blood Pressure / Q000502:physiology; D001808:Blood Vessels / Q000294:innervation / Q000503:physiopathology; D004594:Electrophysiology; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D009638:Norepinephrine / Q000097:blood / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014018:Tissue Distribution
D009638:Norepinephrine