Leptin-sensitive neurons in the arcuate nucleus integrate activity and temperature circadian rhythms and anticipatory responses to food restriction

Michael F Wiater; Ai-Jun Li; Thu T Dinh; Heiko T Jansen; Sue Ritter

doi:10.1152/ajpregu.00032.2013

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Leptin-sensitive neurons in the arcuate nucleus integrate activity and temperature circadian rhythms and anticipatory responses to food restriction

Journal article

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Leptin-sensitive neurons in the arcuate nucleus integrate activity and temperature circadian rhythms and anticipatory responses to food restriction

Michael F Wiater, Ai-Jun Li, Thu T Dinh, Heiko T Jansen and Sue Ritter

American journal of physiology. Regulatory, integrative and comparative physiology, Vol.305(8), pp.R949-960

10/15/2013

DOI: https://doi.org/10.1152/ajpregu.00032.2013

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https://hdl.handle.net/2376/106838

PMCID: PMC3798771

PMID: 23986359

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Abstract

Motor Activity - physiology

Suprachiasmatic Nucleus - drug effects

Motor Activity - drug effects

Rats

Male

Circadian Rhythm - physiology

Arcuate Nucleus of Hypothalamus - physiology

Ribosome Inactivating Proteins, Type 1 - pharmacology

Rats, Sprague-Dawley

Feeding Behavior - physiology

Feeding Behavior - drug effects

Suprachiasmatic Nucleus - physiology

Food Deprivation - physiology

Animals

Arcuate Nucleus of Hypothalamus - drug effects

Neurons - physiology

Leptin - pharmacology

Neurons - drug effects

Circadian Rhythm - drug effects

Previously, we investigated the role of neuropeptide Y and leptin-sensitive networks in the mediobasal hypothalamus in sleep and feeding and found profound homeostatic and circadian deficits with an intact suprachiasmatic nucleus. We propose that the arcuate nuclei (Arc) are required for the integration of homeostatic circadian systems, including temperature and activity. We tested this hypothesis using saporin toxin conjugated to leptin (Lep-SAP) injected into Arc in rats. Lep-SAP rats became obese and hyperphagic and progressed through a dynamic phase to a static phase of growth. Circadian rhythms were examined over 49 days during the static phase. Rats were maintained on a 12:12-h light-dark (LD) schedule for 13 days and, thereafter, maintained in continuous dark (DD). After the first 13 days of DD, food was restricted to 4 h/day for 10 days. We found that the activity of Lep-SAP rats was arrhythmic in DD, but that food anticipatory activity was, nevertheless, entrainable to the restricted feeding schedule, and the entrained rhythm persisted during the subsequent 3-day fast in DD. Thus, for activity, the circuitry for the light-entrainable oscillator, but not for the food-entrainable oscillator, was disabled by the Arc lesion. In contrast, temperature remained rhythmic in DD in the Lep-SAP rats and did not entrain to restricted feeding. We conclude that the leptin-sensitive network that includes the Arc is required for entrainment of activity by photic cues and entrainment of temperature by food, but is not required for entrainment of activity by food or temperature by photic cues.

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Title: Leptin-sensitive neurons in the arcuate nucleus integrate activity and temperature circadian rhythms and anticipatory responses to food restriction
Creators: Michael F Wiater - Programs in Neuroscience, Washington State University, Pullman, Washington
Ai-Jun Li
Thu T Dinh
Heiko T Jansen
Sue Ritter
Publication Details: American journal of physiology. Regulatory, integrative and comparative physiology, Vol.305(8), pp.R949-960
Academic Unit: Integrative Physiology and Neuroscience, Department of
Publisher: United States
Grant note: DK-81546 / NIDDK NIH HHS DK-40498 / NIDDK NIH HHS DA-023202 / NIDA NIH HHS R01 DK040498 / NIDDK NIH HHS
Identifiers: 99900546741901842
Language: English
Resource Type: Journal article