Photoperiodic regulation of satiety mediating neuropeptides in the brainstem of the seasonal Siberian hamster (Phodopus sungorus).
Central regulation of energy balance in seasonal mammals such as the Siberian hamster is dependent on the precise integration of short-term satiety information arising from the gastrointestinal tract with long-term signals on the status of available energy reserves (e.g. leptin) and prevailing photoperiod. Within the central nervous system, the brainstem nucleus of the solitary tract (NTS) and the parabrachial nucleus (PBN) are major relay nuclei that transmit information from the gastrointestinal tract to higher forebrain centres. We extended studies on the seasonal programming of the hypothalamus to examine the effect of the photoperiod on neuropeptidergic circuitries of this gut-brain axis. In the NTS and PBN we performed gene expression and immunoreactivity (-ir) studies on selected satiety-related neuropeptides and receptors: alpha-melanocyte stimulating hormone, melanocortin-3 receptor, melanocortin-4 receptor (MC4-R), growth hormone secretagogue-receptor, cocaine- and amphetamine-regulated transcript, preproglucagon (PPG), glucagon-like peptide 1 (GLP-1), cholecystokinin (CCK), peptide YY, galanin, neurotensin, and corticotrophin releasing hormone (CRH). Gene expression of PPG and MC4-R, and -ir of CCK and GLP-1, in the NTS were up-regulated after 14 weeks in long-day photoperiod (16 h light:8 h dark) compared to short-days (8 h light:16 h dark), whereas CRH-ir and NT-ir were increased in short-days within the PBN. We suggest that brainstem neuroendocrine mechanisms contribute to the long-term regulation of body mass in the Siberian hamster by a photoperiod-related modulation of satiety signalling.
Molecular Nutritional Medicine, Else Kröner-Fresenius Center, Technische Universität München, Am Forum 5, 85350, Freising-Weihenstephan, Germany. michael.helwig@wzw.tum.de
Michael
M
Helwig
Zoë A
ZA
Archer
Gerhard
G
Heldmaier
Alexander
A
Tups
Julian G
JG
Mercer
Martin
M
Klingenspor
D000818:Animals; D031608:Area Postrema / Q000737:chemistry / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D001933:Brain Stem / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D020738:Leptin / Q000494:pharmacology / Q000502:physiology; D008297:Male; D008550:Melatonin / Q000502:physiology; D009479:Neuropeptides / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D017111:Phodopus / Q000502:physiology*; D017440:Photoperiod; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000502:physiology; D012528:Satiety Response / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D012621:Seasons; D017552:Solitary Nucleus / Q000737:chemistry / Q000502:physiology
D020738:Leptin; D009479:Neuropeptides; D018013:Receptors, Neuropeptide; D008550:Melatonin