Journal article
Leptin-sensitive neurons in the arcuate nuclei contribute to endogenous feeding rhythms
American journal of physiology. Regulatory, integrative and comparative physiology, Vol.302(11), pp.R1313-R1326
06/01/2012
Handle:
https://hdl.handle.net/2376/110703
PMCID: PMC3378345
PMID: 22492818
Abstract
Neural sites that interact with the suprachiasmatic nuclei (SCN) to generate rhythms of unrestricted feeding remain unknown. We used the targeted toxin, leptin conjugated to saporin (Lep-SAP), to examine the importance of leptin receptor-B (LepR-B)-expressing neurons in the arcuate nucleus (Arc) for generation of circadian feeding rhythms. Rats given Arc Lep-SAP injections were initially hyperphagic and rapidly became obese (the “dynamic phase” of weight gain). During this phase, Lep-SAP rats were arrhythmic under 12:12-h light-dark (LD) conditions, consuming 59% of their total daily intake during the daytime, compared with 36% in blank-SAP (B-SAP) controls. Lep-SAP rats were also arrhythmic in continuous dark (DD), while significant circadian feeding rhythms were detected in all B-SAP controls. Approximately 8 wk after injection, Lep-SAP rats remained obese but transitioned into a “static phase” of weight gain marked by attenuation of their hyperphagia and rate of weight gain. In this phase, Arc Lep-SAP rats exhibited circadian feeding rhythms under LD conditions, but were arrhythmic in continuous light (LL) and DD. Lep-SAP injections into the ventromedial hypothalamic nucleus did not cause hyperphagia, obesity, or arrhythmic feeding in either LD or DD. Electrolytic lesion of the SCN produced feeding arrhythmia in DD but not hyperphagia or obesity. Results suggest that both Arc Lep-SAP neurons and SCN are required for generation of feeding rhythms entrained to photic cues, while also revealing an essential role for the Arc in maintaining circadian rhythms of ad libitum feeding independent of light entrainment.
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Details
- Title
- Leptin-sensitive neurons in the arcuate nuclei contribute to endogenous feeding rhythms
- Creators
- Ai-Jun Li - Programs in Neuroscience, Washington State University, Pullman, WashingtonMichael F Wiater - Programs in Neuroscience, Washington State University, Pullman, WashingtonMarjolein T Oostrom - Programs in Neuroscience, Washington State University, Pullman, WashingtonBethany R Smith - Programs in Neuroscience, Washington State University, Pullman, WashingtonQing Wang - Programs in Neuroscience, Washington State University, Pullman, WashingtonThu T Dinh - Programs in Neuroscience, Washington State University, Pullman, WashingtonBrandon L Roberts - Programs in Neuroscience, Washington State University, Pullman, WashingtonHeiko T Jansen - Programs in Neuroscience, Washington State University, Pullman, WashingtonSue Ritter - Programs in Neuroscience, Washington State University, Pullman, Washington
- Publication Details
- American journal of physiology. Regulatory, integrative and comparative physiology, Vol.302(11), pp.R1313-R1326
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Identifiers
- 99900547104201842
- Language
- English
- Resource Type
- Journal article