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Cerebral activation by fasting induces lactate accumulation in the hypothalamus
Author(s) -
Violante Inês R.,
Anastasovska Jelena,
SanchezCa Gina J.,
Rodrigues Tiago B.,
Righi Valeria,
NietoCharques Laura,
Parkinson James R.C.,
Bloom Stephen R.,
Bell Jimmy D.,
Cerdán Sebastián
Publication year - 2009
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22010
Subject(s) - medicine , endocrinology , orexigenic , hypothalamus , ghrelin , appetite , chemistry , neuropeptide , neuropeptide y receptor , biology , hormone , receptor
Carbon‐13 ( 13 C) high‐resolution magic angle spinning (HR‐MAS) spectroscopy was used to investigate the neuroglial coupling mechanisms underlying appetite regulation in the brain of C57BL/6J mice metabolizing [1‐ 13 C]glucose. Control fed or overnight fasted mice received [1‐ 13 C]glucose (20 μmol/g intraperitoneally [i.p.]), 15 min prior to brain fixation by focused microwaves. The hypothalamic region was dissected from the rest of the brain and 13 C HR‐MAS spectra were obtained from both biopsies. Fasting resulted in a significant increase in hypothalamic [3‐ 13 C]lactate and [2‐ 13 C]γ‐aminobutyric acid (GABA) relative to the remaining brain. Administration of the orexigenic peptide ghrelin (0.3 nmol/g i.p.) did not increase hypothalamic [3‐ 13 C]lactate or [2‐ 13 C]GABA, suggesting that ghrelin signaling is not sufficient to elicit all the metabolic consequences of hypothalamic activation by fasting. Our results indicate that the hypothalamic regulation of appetite involves, in addition to the well‐known neuropeptide signaling, increased neuroglial lactate shuttling and augmented GABA concentrations. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.