Hypothalamic Norepinephrine: Circadian Rhythms and the Control of Feeding Behavior

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Science  10 Nov 1972:
Vol. 178, Issue 4061, pp. 640-643
DOI: 10.1126/science.178.4061.640


The time of day is a decisive determinant of the effects of l-norepinephrine on feeding behavior. During the dark, direct application of l-norepinephrine to the hypothalamus of rats suppressed feeding behavior. During the light, treatment with the same dose of l-norepinephrine facilitated feeding behavior. Thus, l-norepinephrine has dual and opposite effects on feeding behavior. A hypothalamic substrate that fluctuates in a circadian rhythm could account for both actions of l-norepinephrine.