Neurons of the Rostral Ventrolateral Medulla Contribute to Obesity-Induced Hypertension in Rats

Hypertension. 2007 Mar;49(3):640-6. Epub 2006 Dec 26
Sean D. Stocker; Rachel Meador; Julye M. Adams 

There are several possible mechanisms that contribute to the pathogenesis of obestity induced hypertension. However one of the well studied mechanism is how sympathetic nervous system plays a role in obesity-induced hypertension. In the present study the authors are interested in evaluating the role of sympathetic neurons in the rostral ventro lateral medulla contribution to obesity induced-hypertension. Rats were fed with high fat diet and were segregated into obesity prone and obesity resistant rats based on their weight gain. Mean arterial pressure was significantly elevated in the obesity prone rats than obesity resistant rats. GABA A receptor agonist muscimol decreased mean arterial blood pressure when injected bilaterally into the RVLM. The decrease in MAP was more pronounced in the obesity prone group of rats than other groups. vascular reactivity remained unaltered across the groups in response to phenylephrine and norepinephrine. The authors conclude that the tonic activity of rostral ventrolateral medulla sympathetic neurons contribute to the pathogenesis of obesity- induced hypertension.