Brain orexin promotes obesity resistance.
Resistance to obesity is becoming an exception rather than the norm, and understanding mechanisms that lead some to remain lean in spite of an obesigenic environment is critical if we are to find new ways to reverse this trend. Levels of energy intake and physical activity both contribute to body weight management, but it is challenging for most to adopt major long-term changes in either factor. Physical activity outside of formal exercise, also referred to as activity of daily living, and in stricter form, spontaneous physical activity (SPA), may be an attractive modifiable variable for obesity prevention. In this review, we discuss individual variability in SPA and NEAT (nonexercise thermogenesis, or the energy expended by SPA) and its relationship to obesity resistance. The hypothalamic neuropeptide orexin (hypocretin) may play a key role in regulating SPA and NEAT. We discuss how elevated orexin signaling capacity, in the context of a brain network modulating SPA, may play a major role in defining individual variability in SPA and NEAT. Greater activation of this SPA network leads to a lower propensity for fat mass gain and therefore may be an attractive target for obesity prevention and therapy.
Department of Veterans Affairs, GRECC and Research Service, Minneapolis, Minnesota 55417, USA. kotzx004@umn.edu
Catherine
C
Kotz
Joshua
J
Nixon
Tammy
T
Butterick
Claudio
C
Perez-Leighton
Jennifer
J
Teske
Charles
C
Billington
D000818:Animals; D001921:Brain / Q000378:metabolism*; D004734:Energy Metabolism; D015444:Exercise; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D000068797:Orexins; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D015398:Signal Transduction; D012894:Sleep Stages; D022722:Thermogenesis / Q000502:physiology
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins