Attenuated Sympathetic Activity and Its Relation to Obesity in MSG Injected and Sympathectomized Rats.
- Author:
So Young PARK
1
;
Yong Woon KIM
;
Jin Myoung DAN
;
Jong Yeon KIM
Author Information
1. Department of Physiology, College of Medicine, Yeungnam University, Daegu 705-717, Korea. sypark@med.yu.ac.kr
- Publication Type:Original Article
- Keywords:
MSG rats;
Sympathetic activity;
Obesity;
Demedullation;
Guanethidine
- MeSH:
Animals;
Body Weight;
Epinephrine;
Guanethidine;
Heart Rate;
Obesity*;
Plasma;
Rats*;
Sodium Glutamate*
- From:The Korean Journal of Physiology and Pharmacology
2007;11(4):155-161
- CountryRepublic of Korea
- Language:English
-
Abstract:
In order to characterize the role of sympathetic activity in obesity, we repeatedly assessed sympathetic activity via power spectral analyses of heart rate variability in the same subjects at 7, 11, 25, and 60 weeks, using monosodium glutamate (MSG)-induced obese and control rats. The effects of lower sympathetic activity on obesity were also evaluated. Fat mass in MSG rats was already higher at 7 weeks, but the sympathetic activity did not differ between 7 and 25 weeks. Between 25 and 60 weeks, the increase in fat mass, food efficiency, and body weight gain was higher in MSG rats. The increase in sympathetic activity between 25 and 60 weeks and sympathetic activity at 60 weeks were lower in MSG rats. Fat mass at 60 weeks was inversely correlated with changes in sympathetic activity between 25 and 60 weeks. Reduced plasma epinephrine levels by bilateral adrenal demedullation induced increase of fat mass. In summary, an attenuated increase of sympathetic activity with age may partly be responsible for aggravated obesity in MSG rats. Additionally, reduced sympathetic activity per se induced obesity in rats. These results suggest that lower sympathetic activity contributes to obesity in rats.
