TY - JOUR
T1 - DMV extrasynaptic NMDA receptors regulate caloric intake in rats
AU - Clyburn, Courtney
AU - Travagli, R. Alberto
AU - Arnold, Amy C.
AU - Browning, Kirsteen N.
N1 - Funding Information:
This study was supported by NIH grant DK111667 (KNB) and NIH grant DK 118833 (CC). The graphical abstract was created with BioRender.com. We would like to thank F. Holly Coleman and Sarah S. Bin-gaman for their technical support, particularly with the labeling of gastric-projecting neurons and qPCR experiments, respectively. We would also like to thank W. Nairn Browning as well as Cesare M. and Zoraide Travagli for support and encouragement.
Publisher Copyright:
© 2021, Clyburn et al.
PY - 2021/5/10
Y1 - 2021/5/10
N2 - Acute high-fat diet (aHFD) exposure induces a brief period of hyperphagia before caloric balance is restored. Previous studies have demonstrated that this period of regulation is associated with activation of synaptic N-methyl-D-aspartate (NMDA) receptors on dorsal motor nucleus of the vagus (DMV) neurons, which increases vagal control of gastric functions. Our aim was to test the hypothesis that activation of DMV synaptic NMDA receptors occurs subsequent to activation of extrasynaptic NMDA receptors. Sprague-Dawley rats were fed a control or high-fat diet for 3–5 days prior to experimentation. Whole-cell patch-clamp recordings from gastric-projecting DMV neurons; in vivo recordings of gastric motility, tone, compliance, and emptying; and food intake studies were used to assess the effects of NMDA receptor antagonism on caloric regulation. After aHFD exposure, inhibition of extrasynaptic NMDA receptors prevented the synaptic NMDA receptor–mediated increase in glutamatergic transmission to DMV neurons, as well as the increase in gastric tone and motility, while chronic extrasynaptic NMDA receptor inhibition attenuated the regulation of caloric intake. After aHFD exposure, the regulation of food intake involved synaptic NMDA receptor–mediated currents, which occurred in response to extrasynaptic NMDA receptor activation. Understanding these events may provide a mechanistic basis for hyperphagia and may identify novel therapeutic targets for the treatment of obesity.
AB - Acute high-fat diet (aHFD) exposure induces a brief period of hyperphagia before caloric balance is restored. Previous studies have demonstrated that this period of regulation is associated with activation of synaptic N-methyl-D-aspartate (NMDA) receptors on dorsal motor nucleus of the vagus (DMV) neurons, which increases vagal control of gastric functions. Our aim was to test the hypothesis that activation of DMV synaptic NMDA receptors occurs subsequent to activation of extrasynaptic NMDA receptors. Sprague-Dawley rats were fed a control or high-fat diet for 3–5 days prior to experimentation. Whole-cell patch-clamp recordings from gastric-projecting DMV neurons; in vivo recordings of gastric motility, tone, compliance, and emptying; and food intake studies were used to assess the effects of NMDA receptor antagonism on caloric regulation. After aHFD exposure, inhibition of extrasynaptic NMDA receptors prevented the synaptic NMDA receptor–mediated increase in glutamatergic transmission to DMV neurons, as well as the increase in gastric tone and motility, while chronic extrasynaptic NMDA receptor inhibition attenuated the regulation of caloric intake. After aHFD exposure, the regulation of food intake involved synaptic NMDA receptor–mediated currents, which occurred in response to extrasynaptic NMDA receptor activation. Understanding these events may provide a mechanistic basis for hyperphagia and may identify novel therapeutic targets for the treatment of obesity.
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U2 - 10.1172/jci.insight.139785
DO - 10.1172/jci.insight.139785
M3 - Article
C2 - 33764905
AN - SCOPUS:85106319877
VL - 6
JO - JCI insight
JF - JCI insight
SN - 2379-3708
IS - 9
M1 - e139785
ER -