title: Rapid glutamate release in the mediobasal hypothalamus accompanies feeding and is exaggerated by an obesogenic food.
abstract: The mediobasal hypothalamus (MBH) plays a central role in the regulation of food intake and energy balance. Although the excitatory neurotransmitter glutamate is implicated in energy balance regulation by the MBH, the hypothesis that feeding elicits local glutamate release remains untested. To test this hypothesis, we employed a glutamate biosensor that measures glutamate concentrations at 1-s intervals in conscious, freely behaving rats. Results indicate that feeding is associated with an increase of MBH glutamate concentration that occurs within 1-2 s of oral contact with a food pellet, and the glutamate response to a palatable high-fat pellet is greatly exaggerated relative to chow. In contrast, glutamate responses were not observed during water ingestion or other observed behaviors. These findings indicate that feeding is associated with rapid release of glutamate in the MBH, that this release is exaggerated with an obesogenic food, and that this response is likely stimulated by orosensory factors.
authors.affiliation: Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, UW Medicine at South Lake Union, 850 Republican Street, Box 358055, Seattle, WA 98109, USA.
authors.forename: Stephan J
authors.initials: SJ
authors.lastname: Guyenet
authors.forename: Miles E
authors.initials: ME
authors.lastname: Matsen
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Morton
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Kaiyala
authors.forename: Michael W
authors.initials: MW
authors.lastname: Schwartz
keywords: Arcuate nucleus; Food intake; Glutamate; High-fat diet; Hypothalamus