Effects of area postrema/caudal medial nucleus of solitary tract lesions on food intake and body weight.

Lesions of the area postrema/caudal medial nucleus of the solitary tract (AP/cmNTS), located on the surface of the dorsal medulla of the rat, cause a transient syndrome of hypophagia and body weight loss, with the establishment of a new growth curve at a lower body weight set point. The regulatory responses to prolonged food deprivation, glucoprivic stimulation, and chronic access to a palatable diet are left largely intact. However, there is an overconsumption of highly palatable foods during acute exposure to supermarket and high-fat diets. Intestinal transit and gastric retention are unaffected by the lesion, indicating normal motor function within the gastrointestinal system. The hypophagia and chronic depression of body weight by the AP/cmNTS lesion demonstrate that this area is an important part of the larger neurocircuitry subserving feeding behavior and energy balance.