Lumbar sympathectomy does not attenuate the development of mild DOCA‐salt hypertension

Abstract

Increased sympathetic nervous activity (SNA), responsible for the development and maintenance of hypertension, is more prominent in some vascular beds than others. Previous studies in anesthetized DOCA‐salt hypertensive rats show that elevated hindlimb vascular resistance is mediated in part through higher lumbar SNA. This indicates that increased lumbar SNA could be a cause of hypertension in DOCA‐salt rats. The purpose of this study was to evaluate in conscious rats the importance of lumbar SNA to the development of mild DOCA‐salt hypertension. To accomplish this goal, chronic lumbar sympathectomy was performed in one group of male Sprague Dawley rats (n=8) while another group underwent SHAM operation (n=8). During the same operation, rats were instrumented with a radiotelemeter for blood pressure (BP) and heart rate (HR) measurements. Rats were allowed free access to water containing 1% NaCl and 0.2% KCl. After a 7 day recovery and a 3 day control BP measurement period, a DOCA pellet (50 mg/kg, SC) was implanted in both groups. BP was then measured for another 4 weeks. During the control period, BP and HR were similar in the two groups. Following DOCA treatment, BP increased similarly in both groups. HR also was not different between the two groups during the development of hypertension. We conclude that lumbar SNA is not critical in the development of mild DOCA‐salt hypertension. Supported by PO1‐HL070687.