Six articles in the May 2005 issue of Nature Neuroscience review the literature on the neurobiology of feeding regulation, and how it can go awry.
Severe overweight (obesity) now affects 15?30% of the population in many Western countries. Obesity can seriously affect health and quality of life, but still overweight people find it very difficult to lose the excess pounds. The solution looks simple - anyone should lose weight if they eat fewer calories than they burn - but in fact eating and body weight are subject to complex regulation, and some of these physiological mechanisms can sabotage dieters. If we want to combat the obesity epidemic with more effective means than just appeals to sensible eating and exercise, we must develop a better understanding of how the body and brain regulate food intake and fat storage.
Three articles focus on the hypothalamus - a brain structure that is intimately connected to the body's hormone systems and the master regulator of energy metabolism. Roger Cone reviews the function of nerve circuits that signal via melanocortin - an unusual neurotransmitter - and are important in feeding regulation. Luciano Rossetti and colleagues explain how the hypothalamus measures the body's level of available nutrients. Tamas Horvath reports on surprising findings that nerve cell connections in the hypothalamus can change rapidly depending on whether an animal is hungry or has just eaten.
The hormone leptin is produced by fat cells and normally signals through the hypothalamus to reduce feeding, but this mechanism appears disturbed in obese animals and people. Heike Münzberg and Martin Myers explain what goes wrong with leptin signaling on a molecular level.
Finally, we all know that eating can be a source of pleasure and comfort. This has inspired neuroscientists to investigate possible parallels between overeating and drug addiction. Nora Volkow and Roy Wise discuss the results of this work. In fact, the same receptor that is responsible for the effects of marijuana also increases eating. Vincenzo Di Marzo and Isabel Matias review new insights into the function of this receptor, as well as clinical studies that suggest it could be a target for weight loss drugs.
Publication of these articles in Nature Neuroscience is sponsored by the Obesity Research Task Force of the National Institutes of Health, Bethesda, Maryland, USA.
Roger Cone (Oregon Health Sciences University, Vollum Institute, Portland, OR, USA)
Luciano Rossetti (Albert Einstein College of Medicine, Bronx, NY, USA)
Tamas Horvath (Yale Medical School, New Haven, CT, USA)
Martin Myers (University of Michigan Medical School, Ann Arbor, MI, USA)
Nora Volkow (National Institute on Drug Abuse, Bethesda, MD, USA)
Vincenzo Di Marzo (Istituto per la Chimica di Molecole di Interesse Biologico, Consiglio Nazionale delle Ricerche, Naples, Italy)
Lisa Gansheroff (NIDDK - National Institutes of Health, Bethesda, MD, USA)
(C) Nature Neuroscience press release.
Message posted by: Trevor M. D'Souza