[Abstract Title]. - Society for Neuroscience

Abstract: Recent studies have shown the expression of nutrient-sensing systems transmitting
nutritive information from the gastrointestinal tract to the brain. However brain activity induced
by ingested nutrients has not been investigated. The first goal of the present study was, using
functional magnetic resonance imaging, to determine dynamic neural activity following
intragastric nutrients (glucose, L-glutamate and NaCl) administration. Rats were anesthetized
with alpha-chloralose and after 30 min, MRI scanning was started. Thirty min after the start of
scanning, 60 mM NaCl, monosodium L-glutamate (MSG), glucose, or 150 mM NaCl solution
was infused into the stomach through a cannula for 10 min and then scanning was lasted for 50
min. Our data clearly demonstrated that post-ingestive nutrient-specific neural activity was
observed in several forebrain regions including the nucleus accumbens, hypothalamus, and
limbic system with different timings. Second, we assessed a role of the vagal afferent nerve on
transmitting nutrient signals from gastrointestinal tract to the brain using rats with
subdiaphragmatic total vagotomy (TVX). TVX eliminated substantially the MSG and NaClinduced
activation. On the contrary, TVX did not affect glucose-induced brain activity. These
results indicate that postingestive nutrient-induced neural activity in the forebrain is due to the
distinct pathway transmitting from the gut to the brain.
Disclosures: T. Tsurugizawa, None; T. Kondoh, None; A. Uematsu, None; K. Torii, None.
Poster
284. Regulation of Food Intake and Body Weight: Integration of Peripheral Signals:
Systems
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 284.17/QQ12
Topic: E.07.b. Integration of peripheral signals: Systems
Support: NIH Grant DK78056
Title: Novel molecular tracing techniques to study the neural mechanisms of leptin action
Authors: *G. W. LOUIS 1 , G. M. LEINNINGER 1 , C. J. RHODES 2 , M. G. MYERS 1 ;
1 Univ. Michigan, Ann Arbor, MI; 2 Univ. of Chicago, Chicago, IL
Abstract: Leptin, which is secreted by adipocytes as a signal of energy stores, acts via the long
form of the leptin receptor (LepRb) in the hypothalamus and other areas of the brain to regulate
energy balance and neuroendocrine function. Many regions involved in the regulation of energy
balance contain large groups of LepRb-expressing neurons, including intensively studied “satiety
centers" (such as the arcuate nucleus (ARC)), and “feeding centers” (such as the lateral
hypothalamic area (LHA)). The LHA contains two well-described populations of orexigenic