ICEECE2012 Poster Presentations Obesity (114 abstracts)
1University of Santiago de Compostela-Instituto de Investigacion Sanitaria (IDIS), Santiago de Compostela, Spain; 2Instituto Carlos III (ISCIII), Madrid, Spain; 3NIHR Cambridge Biomedical Research Centre Addenbrookes Hospital, University of Cambridge, Cambridge, UK; 4University of Bergen, Bergen, Norway; 5Haukeland University Hospital, Bergen, Norway.
Introduction: Smokers around the globe commonly report increased body weight after smoking cessation as a major factor that interferes with their attempts to quit. In addition, numerous controlled studies in both humans and rodents have reported that nicotine exerts a marked anorectic action. Nicotines effects on energy homeostasis have been mostly pinpointed in the central nervous system, but the molecular mechanisms controlling its action are still not fully understood.
Objective: The aim of this study was to investigate the effect of nicotine on hypothalamic AMPK and its effect on feeding and brown adipose tissue function.
Methods: We used adult male SpragueDawley rats. Subcutaneous and intracerebroventricular treatments. Stereotaxic microinjection of adenoviral expression vectors. Analysis by in situ hybridization, enzymatic assays, western blotting and real-time quantitative PCR. Analysis of energy expenditure, locomotor activity, respiratory quotient and lipid utilization. Nuclear magnetic resonance analysis.
Results: Here, we demonstrate that nicotine-induced weight loss is associated with decreased orexigenic signaling in the hypothalamus, inactivation of hypothalamic AMP-activating protein kinase, alterations in fuel substrate utilization and upregulation of thermogenic markers in brown adipose tissue. Conversely, nicotine withdrawal or genetic activation of hypothalamic AMPK in the ventromedial nucleus of the hypothalamus reversed nicotine-induced hypophagia and weight loss.
Conclusions: Overall, these data demonstrate that nicotines effects on energy balance involve specific modulation of the hypothalamic AMP-activating protein kinase-brown adipose tissue axis.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.