Sympathetic Nervous System and Hypertension
With the development and implementation of device-based therapeutic interventions to decrease renal and systemic nerve activity in patients with resistant hypertension, there has been an increase in research dealing with the role of the sympathetic nervous system in hypertension. These interventions have produced substantial decreases in blood pressure in patients wherein pharmacological treatments, including agents which inhibit the effects of the renin–angiotensin–aldosterone system, have failed serves to confirm and reassert the essential role of the sympathetic nervous system in hypertension. This review will encompass recent publications dealing with the sympathetic nervous system and hypertension, focusing on those recently published in Hypertension.
Sympathetic Activation in Animal Models
Although there has been a debate as to whether sympathetic activation is a cause or consequence of obesity, the studies noted below support the view that it is the obesity that leads to sympathetic activation. The importance of this sympathetic activation for the development of the hypertension is supported by the finding that renal denervation prevents the development of obesity hypertension in the dog.
Studies have now focused on the developmental phase of obesity hypertension regarding the renal sympathoexcitation. In rabbits fed high-fat diets, body weight, plasma insulin and leptin concentrations, mean arterial pressure, heart rate, and renal sympathetic nerve activity were all increased after 1 week.1 Mean arterial pressure and body weight continued to increase over 3 weeks of high-fat diet, whereas heart rate and renal sympathetic nerve activity did not change further. Arterial baroreflex control of renal sympathetic nerve activity was attenuated from the first week of the high-fat diet. Excitatory responses to air jet stress diminished over 3 weeks of high-fat diet. Resumption of normal diet normalized glucose, insulin, leptin, and heart rate, but body weight, visceral fat content, mean arterial pressure, and renal sympathetic nerve activity remained elevated. Increased renal sympathetic nerve activity …