Chemical sympathectomy alters regulation of body weight during prolonged ICV leptin infusion.
To assess the importance of the sympathetic nervous system in regulating body weight during prolonged leptin infusion, we evaluated food intake, body weight, and physical activity in conscious, unrestrained rats. Initial studies illustrated that prolonged intracerebroventricular (ICV) infusion of leptin enhanced substrate oxidation so that adipose tissue lipid stores were completely ablated, and muscle triglyceride and liver glycogen stores were depleted. After neonatal chemical sympathectomy, changes in weight and food intake were compared in groups of sympathectomized (SYM) and control (CON) adult animals during ICV infusion of leptin. CON animals lost 60 +/- 9 g over 10 days vs. 25 +/- 3 g in the SYM animals when food intake was matched between the two groups. Greater weight loss despite similar energy intake points to an important role of the sympathetic nervous system in stimulating energy expenditure during ICV leptin infusion by increasing the resting metabolic rate, since no differences in physical activity were observed between CON and SYM groups. In conclusion, activation of the SNS by leptin increases energy expenditure by augmenting the resting metabolic rate.
Dobbins
Robert L
RL
Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9135, USA. robert.dobbins@utsouthwestern.edu
Szczepaniak
Lidia S
LS
Zhang
Weiguo
W
McGarry
J Denis
JD
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose; D001835:Body Weight / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007276:Injections, Intraventricular; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D013563:Sympathectomy, Chemical; D013564:Sympathetic Nervous System / Q000502:physiology*; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D020738:Leptin; D014280:Triglycerides