Controlling weight gain and overcoming eating disorders such as anorexia might soon be achieved by understanding how the brain controls appetite and decides how much to eat.
The brain monitors food intake, energy needs and how much energy to store as fat by regulating hormones such as leptin and insulin. As any dieter knows, reduce food intake and the brain quickly responds by increasing appetite to keep the energy regulation system in balance.
Delegates to the American Association for the Advancement of Science in Philadelphia will today hear speakers explain how regulating the brain's energy control system might produce new treatments for the overweight and provide a pharmaceutical approach to reversing the effects of anorexia. A person's body-fat stores remain relatively constant despite variations in food intake and energy demands, according to Dr Michael W. Schwartz of the University of Washington in Seattle. An overweight or an anorexic person can, of course, wilfully override this natural control mechanism to cause long-term changes in body fat.
He is studying the brain's biochemical regulatory system and its response to levels of insulin and leptin and the cascade of substances produced when these hormones are present. For example, severe obesity can occur if the leptin-producing gene carries a mutation which keeps leptin in short supply. There may also be problems with the locations in the brain which respond to leptin.
Understanding these biochemical reactions provides a framework for understanding common disturbances of body-weight regulation, Dr Schwartz said. Learning how these biochemicals interact could lead to drugs which help control their action in overweight or anorexic patients.
Similar work on the body's complex chemistry is under way regarding pain management. Researchers are seeking new ways to control neuropathic or nerve injury pain. this pain was one of the "most significant health problems in our country", said Prof Frank Porreca of the University of Arizona. It affects one in eight people in the US.
It is usually difficult to control with existing drugs. He is studying the production of a substance arising from nerve damage called spinal dynorphin. Elevated levels of this biochemical "appear to be intimately involved in either the initiation or maintenance of nerve-injury-related pain".
Researchers have yet to learn what it does or where in the body it interacts, but this knowledge could help produce drugs to block dynorphin's action.
Prof Joyce A. DeLeo at the University of Dartmouth School of Medicine is researching the link between neuropathic pain and another substance, spinal cytokines, which are related to the body's own immune response. "We have found evidence that immune activation contributes to the generation of chronic pain states," she said.