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Papers of the Week

Papers: 6 May 2023 - 12 May 2023

Basic Science

Animal Studies, Molecular/Cellular, Neurobiology, Sex Differences

Abdominal/Pelvic Pain, Acute Pain, Inflammation/Inflammatory

2023 Apr 30

Exp Neurobiol




A Critical Involvement of Glutamatergic Neurons in the Anterior Insular Cortex for Subdiaphragmatic Vagotomy-induced Analgesia.


Kim YJ, Lee GJ, Shim SW, Kim D, Oh SB


Subdiaphragmatic vagotomy (SDV) is known to produce analgesic effect in various pain conditions including not only visceral pain but also somatic pain. We aimed to determine brain mechanisms by which SDV induces analgesic effect in somatic pain condition by using formalin-induced acute inflammatory pain model. We identified brain regions that mediate SDV-induced analgesic effect on acute inflammatory pain by analyzing c-Fos expression in the whole brain. We found that c-Fos expression was specifically increased in the anterior insular cortex (aIC) among subregions of the insular cortex in acute inflammatory pain, which was reversed by SDV. These results were not mimicked in female mice, indicating sexual-dimorphism in SDV-induced analgesia. SDV decreased c-Fos expressions more preferentially in glutamatergic neurons rather than GABAergic neurons in the aIC, and pharmacological activation of glutamatergic neurons with NMDA in the aIC inhibited SDV-induced analgesic effect. Furthermore, chemogenetic activation of glutamatergic neurons in the aIC reversed SDV-induced analgesia. Taken together, our results suggest that the decrease in the neuronal activity of glutamatergic neurons in the aIC mediates SDV-induced analgesic effect, potentially serving as an important therapeutic target to treat inflammatory pain.