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Ramadhani A, Sofro ZM, Partadiredja G. The effect of oral administration of monosodium glutamate on orofacial pain response and the estimated number of trigeminal ganglion sensory neurons of male Wistar rats. BIO WEB OF CONFERENCES 2021. [DOI: 10.1051/bioconf/20214105007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Monosodium glutamate (MSG) is a worldwide flavor enhancer. The excessive glutamate concentration in nerve tissue induces the death of nerve cells, known as excitotoxicity. In the orofacial region, the nerve cells’ death affects pain perception such as mechanical hyperalgesia and allodynia. The aim of the present study was to examine the pain response modification and the estimated total number of trigeminal ganglion sensory neurons after sub chronic oral administration of MSG. Twenty eight male Wistar rats, aged 6-8 weeks (100-150 grams) were divided into 4 groups: Control (2 mL NaCl 0.9%); 1 mg/gWB MSG; 2 mg/gWB MSG; 4 mg/gWB MSG groups. Daily oral administration of MSG was given for 30 days. The control group received NaCl per oral for the same period. The pin prick and air puff test were performed on days 1-2, days 41-42 and days 55-56. The number of trigeminal ganglion sensory neurons were estimated by the unbiased stereology method, using the approach of numerical density and organ volume reference. The results showed that the sub chronic oral administration of MSG does not modify either the orofacial pain response or the estimated total number of trigeminal ganglion sensory neurons. .
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Lin J, Liu F, Zhang YY, Song N, Liu MK, Fang XY, Liao DQ, Zhou C, Wang H, Shen JF. P2Y 14 receptor is functionally expressed in satellite glial cells and mediates interleukin-1β and chemokine CCL2 secretion. J Cell Physiol 2019; 234:21199-21210. [PMID: 31032956 DOI: 10.1002/jcp.28726] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 02/05/2023]
Abstract
Satellite glial cells (SGCs) activation in the trigeminal ganglia (TG) is critical in various abnormal orofacial sensation in nerve injury and inflammatory conditions. SGCs express several subtypes of P2 purinergic receptors contributing to the initiation and maintenance of neuropathic pain. The P2Y14 receptor, a G-protein-coupled receptor activated by uridine diphosphate (UDP)-glucose and other UDP sugars, mediates various physiologic events such as immune, inflammation, and pain. However, the expression, distribution, and function of P2Y14 receptor in SGCs remains largely unexplored. Our study reported the expression and functional identification of P2Y14 receptor in SGCs. SGCs were isolated from TG of rat, and the P2Y14 receptor expression was examined using immunofluorescence technique. Cell proliferation and viability were examined via cell counting kit-8 experiment. Immunofluorescence demonstrated the presence of P2Y14 receptor in SGCs. Immunofluorescence and western blot showed that UDP-glucose treatment upregulated glial fibrillary acid protein, a common marker for glial activation. Extracellular UDP-glucose enhanced the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, which were both abolished by the P2Y14 receptor inhibitor (PPTN). Furthermore, quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay demonstrated that extracellular UDP-glucose significantly enhanced interleukin-1β (IL-1β) and chemokine CCL2 (CCL2) release, which was abolished by PPTN and significantly decreased by inhibitors of MEK/ERK (U0126) and p38 (SB202190). Our findings directly proved the functional presence of P2Y14 receptor in SGCs. It was also verified that P2Y14 receptor activation was involved in activating SGCs, phosphorylating MAPKs, and promoting the secretion of IL-1β and CCL2 via ERK and p38 pathway.
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Affiliation(s)
- Jiu Lin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Fei Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yan-Yan Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ning Song
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Meng-Ke Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xin-Yi Fang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Da-Qing Liao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
| | - Hang Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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