Modulatory effects of repeated psychophysical stress on masseter muscle nociception in the nucleus raphe magnus of rats
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- Shimizu Shiho
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
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- Nakatani Yosuke
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
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- Kurose Masayuki
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences
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- Imbe Hiroki
- Department of Physiology, Wakayama Medical University
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- Ikeda Nobuyuki
- Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
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- Takagi Ritsuo
- Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
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- Yamamura Kensuke
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences
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- Okamoto Keiichiro
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences
抄録
<p>Psychophysical stress can cause neural changes that increase nociception in the orofacial region, particularly the masseter muscle (MM). The nucleus raphe magnus (NRM), which is located in the brain stem, serves the crucial role of regulating nociception through descending modulatory pain control. However, it remains unclear if neural activities in the NRM are affected under psychophysical stress conditions. This study conducted experiments to assess (1) whether neural activity, indicated by Fos expression in an NRM that has experienced MM injury, is affected by the stress of repeated forced swim tests (FST); and (2) whether the selective serotonin reuptake inhibitor fluoxetine administered daily after an FST could affect the number of Fos-positive neurons in the NRM. Results revealed that the stress from repeated FSTs significantly increased the number of Fos-positive neurons in an NRM that had been affected by MM injury. Fluoxetine inhibited increases in the number of Fos-positive neurons in the NRM that occurred as a result of FSTs, but this was not observed in sham rats. These findings indicate that the stress from FSTs could increase nociceptive neural activity in an NRM that has experienced MM injury. This could be due, in part, to changes in serotonergic mechanisms.</p>
収録刊行物
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- Ｊｏｕｒｎａｌ ｏｆ Ｏｒａｌ Ｓｃｉｅｎｃｅ
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Ｊｏｕｒｎａｌ ｏｆ Ｏｒａｌ Ｓｃｉｅｎｃｅ 62 (2), 231-235, 2020
日本大学歯学部