Effects of norepinephrine infused in the paraventricular hypothalamus on energy expenditure in the rat.
The metabolic effects of norepinephrine (NE), when infused into the paraventricular nucleus of the hypothalamus (PVN), were examined using indirect calorimetry. In two separate experiments, it was found that NE infused into the PVN reduced energy expenditure in freely moving rats. While NE also reduced motor activity, these reductions were not statistically significant. Reductions in voluntary motor activity were not necessary for a reduction in energy expenditure, as NE still reduced energy expenditure in rats that were lightly sedated. Clonidine, but not L-phenylephrine, mimicked the hypometabolic effect of NE, suggesting an action at alpha 2 receptors. Infusions of NE were also found to increase blood glucose shortly after infusion, although the specificity of this effect is questionable. Taken together, these data suggest that activation of noradrenergic neurons within the PVN results in a metabolic shift towards energy conservation.
Siviy
S M
SM
Department of Psychology, University of Sydney, NSW, Australia.
Kritikos
A
A
Atrens
D M
DM
Shepherd
A
A
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002151:Calorimetry; D004734:Energy Metabolism; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology* / Q000502:physiology; D010101:Oxygen Consumption; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D009638:Norepinephrine