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Molinas AJR, Desmoulins LD, Davis RK, Gao H, Satou R, Derbenev AV, Zsombok A. High-Fat Diet Modulates the Excitability of Neurons within the Brain-Liver Pathway. Cells 2023; 12:1194. [PMID: 37190103 PMCID: PMC10137256 DOI: 10.3390/cells12081194] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/14/2023] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Stimulation of hepatic sympathetic nerves increases glucose production and glycogenolysis. Activity of pre-sympathetic neurons in the paraventricular nucleus (PVN) of the hypothalamus and in the ventrolateral and ventromedial medulla (VLM/VMM) largely influence the sympathetic output. Increased activity of the sympathetic nervous system (SNS) plays a role in the development and progression of metabolic diseases; however, despite the importance of the central circuits, the excitability of pre-sympathetic liver-related neurons remains to be determined. Here, we tested the hypothesis that the activity of liver-related neurons in the PVN and VLM/VMM is altered in diet-induced obese mice, as well as their response to insulin. Patch-clamp recordings were conducted from liver-related PVN neurons, VLM-projecting PVN neurons, and pre-sympathetic liver-related neurons in the ventral brainstem. Our data demonstrate that the excitability of liver-related PVN neurons increased in high-fat diet (HFD)-fed mice compared to mice fed with control diet. Insulin receptor expression was detected in a population of liver-related neurons, and insulin suppressed the firing activity of liver-related PVN and pre-sympathetic VLM/VMM neurons in HFD mice; however, it did not affect VLM-projecting liver-related PVN neurons. These findings further suggest that HFD alters the excitability of pre-autonomic neurons as well as their response to insulin.
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Affiliation(s)
- Adrien J. R. Molinas
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Lucie D. Desmoulins
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Roslyn K. Davis
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Hong Gao
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Ryousuke Satou
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Andrei V. Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
- Tulane Brain Institute, Tulane University, New Orleans, LA 70130, USA
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
- Tulane Brain Institute, Tulane University, New Orleans, LA 70130, USA
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Royo M, Escolano BA, Madrigal MP, Jurado S. AMPA Receptor Function in Hypothalamic Synapses. Front Synaptic Neurosci 2022; 14:833449. [PMID: 35173598 PMCID: PMC8842481 DOI: 10.3389/fnsyn.2022.833449] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022] Open
Abstract
AMPA receptors (AMPARs) are critical for mediating glutamatergic synaptic transmission and plasticity, thus playing a major role in the molecular machinery underlying cellular substrates of memory and learning. Their expression pattern, transport and regulatory mechanisms have been extensively studied in the hippocampus, but their functional properties in other brain regions remain poorly understood. Interestingly, electrophysiological and molecular evidence has confirmed a prominent role of AMPARs in the regulation of hypothalamic function. This review summarizes the existing evidence on AMPAR-mediated transmission in the hypothalamus, where they are believed to orchestrate the role of glutamatergic transmission in autonomous, neuroendocrine function, body homeostasis, and social behavior.
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