Regional sympathetic activity in pre-hypertensive phase of spontaneously hypertensive rats.

Imbalances in central and peripheral sympathetic nervous system (SNS) activity have been observed in essential and experimental hypertension. This study was carried out in order to evaluate SNS activity in two distinct tissue types of spontaneously hypertensive rats (SHR), compared to Wistar-Kyoto normotensive (WKY) rats, in the pre-hypertensive phase (4-5 weeks of age). Interstitial concentrations of norepinephrine (NE) and other catecholamines were measured by microdialysis in striated muscle, whose tone is controlled by baroreflexes, and in the subcutaneous adipose tissue where sympathetic output mainly controls metabolism.