Our laboratory focuses on brain sites and substrates mediating energy balance, in obesity prone and obesity-resistant animal models. The goal of our laboratory is to understand brain mechanisms important in determining the popensity for obesity. These investigations involve study of neuropeptides that regulate feeding behavior and energy expenditure, including that related to physical activity. Our most recent focus is on the role of orexin, also known as hypocretin. Orexin is a recently identified neuropeptide predominantly located in the lateral hypothalamus that enhances feeding and physical activity, and which also modifies sleep/wake patterns. Our laboratory has shown that orexin elevates non-volitional low-level activity, which has an important impact on body weight control. We have also shown that this low level activity may be important in maintaing obesity resistance during aging. The techniques we use include stereotaxic surgery, immunohistochemistry, food intake measurements, physical activity chamber measurements, indirect calorimetry, body composition (EchoNMR) radioimmunoassay and molecular biology procedures, including RNA/DNA extraction, northern blots, slot blots, rtPCR, cDNA probe synthesis, random primer labeling, hybridization, densitometry and microarrays.