Calorie Restriction inhibits Sympathetic Nerve Activity via Anti-Oxidant Effect in the Rostral Ventrolateral Medulla of Obesity-Induced Hypertensive Rats

Abstract

In the patients and animals with metabolic syndrome (MetS), sympathetic nerve activity (SNA) is increased. We have demonstrated that oxidative stress in the rostral ventrolateral medulla (RVLM), a vasomotor center in the brainstem, increases SNA. The aim of the present study was to determine whether calorie restriction inhibits SNA via anti-oxidant effect in the RVLM of obesity-induced obesity rats. Male Sprague-Dawley rats were fed on a high-fat diet and segregated into obesity-prone (OP) showing a MetS profile and obesity-resistant (OR) after 13 weeks. Obesity-prone was divided into OP treated with calorie restriction (CR-OP) for 8 weeks and control (CTR-OP). Systolic blood pressure (SBP), heart rate (HR), SNA, and thiobarbituric acid-reactive substances (TBARS) levels as a marker of oxidative stress in the RVLM were significantly higher and the depressor effects due to the microinjection of tempol, a superoxide dismutase mimetic into the RVLM, were significantly greater in OP than in OR. Body weight was significantly lower in CR-OP than in CTR-OP. SBP, HR, SNA, TBARS, and the depressor effects due to the microinjection of tempol into the RVLM were significantly lower in CR-OP than in CTR-OP. These results suggest that calorie restriction inhibits SNA via anti-oxidant effect in the RVLM of obesity-induced obesity rats.

• calorie restriction
• metabolic syndrome
• sympathetic nerve activity
• oxidative stress
• brain

ACKNOWLEDGMENTS

This study was supported by a grant-in-aid for scientific research from the Japan Society for the Promotion of Science (B19390231) and, in part, by the Health and Labor Sciences Research Grant for Comprehensive Research in Aging and Health Labor and Welfare of Japan. We express thanks to Satomi and Jiro.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the papers.