Age-Related Differences in Transient Receptor Potential Vanilloid 1 and 2 Expression Patterns in the Trigeminal Ganglion Neurons Contribute to Changes in the Palatal Mucosal Heat Pain Sensitivity
Age-Related Differences in Transient Receptor Potential Vanilloid 1 and 2 Expression Patterns in the Trigeminal Ganglion Neurons Contribute to Changes in the Palatal Mucosal Heat Pain Sensitivity
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DOI：
10.1620/tjem.2022.j004
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发表时间：
2022-04-01
影响因子：
2.2
通讯作者：
Shinoda, Masamichi
中科院分区：
文献类型：
--
作者：
Oto, Tatsuki;Urata, Kentaro;Shinoda, Masamichi
衰老影响身体的各种感觉功能。但其对口腔粘膜伤害性感受的影响尚不清楚，因此阐明其作用机制具有重要意义。因此，本研究旨在评估三叉神经节（TG）神经元中瞬时受体电位香草酸1（TRPV 1）和TRPV 2表达的年龄相关变化对加速衰老小鼠易感8（SAMP 8）模型口腔粘膜热敏感性的影响。我们使用了23周龄（老年）和7周龄（年轻）的SAMP 8小鼠。在轻度麻醉下对腭粘膜进行热刺激，并测定热头退缩阈值（HHWT）。我们计数了支配腭粘膜的TRPV 1免疫反应（IR）和TRPV 2免疫反应TG神经元的数量。此外，我们还研究了将TRPV 1或TRPV 2拮抗剂（SB 366791或曲尼司特）给予腭粘膜时HHWT的变化。老年SAMP 8小鼠的HHWT高于年轻SAMP 8小鼠。与老年SAMP 8小鼠相比，年轻SAMP 8小鼠显示出更多的TRPV 1-IR小直径神经元和更少的TRPV 2-IR中型神经元支配腭粘膜。SB 366791给药增加了年轻SAMP 8小鼠的HHWT，但未增加老年SAMP 8小鼠的HHWT。相比之下，曲尼司特给药增加了老年SAMP 8小鼠的HHWT，而不是年轻的SAMP 8小鼠。这些结果表明，调制的热痛敏感性在口腔粘膜由于老化是依赖于在支配腭粘膜的TG神经元中的TRPV 1和TRPV 2的表达模式的变化。
Aging affects various sensory functions of the body. However, the effect on the oral mucosal nociception has remain unclear, so this elucidation is very important. Therefore, this study aimed to evaluate the effect of age-related changes in transient receptor potential vanilloid 1 (TRPV1) and TRPV2 expression in the trigeminal ganglion (TG) neurons on intraoral mucosal heat sensitivity in the senescence-accelerated mouse prone 8 (SAMP8) model. We used 23-week-old (aged) and 7-week-old (young) SAMP8 mice. Heat stimulation was applied to the palatal mucosa under light anesthesia; moreover, the heat head withdrawal threshold (HHWT) was measured. We counted the number of TRPV1-immunoreactive (IR) and TRPV2-IR TG neurons innervating the palatal mucosa. Additionally, we investigated changes in HHWT when TRPV1 or TRPV2 antagonists (SB366791 or Tranilast) were administered to the palatal mucosa. Aged SAMP8 mice showed a higher HHWT than young SAMP8 mice. Compared with the aged SAMP8 mice, young SAMP8 mice showed a larger number of TRPV1-IR small-diameter neurons and a smaller number of TRPV2-IR medium-sized neurons innervating the palatal mucosa. SB366791 administration increased the HHWT in young, but not aged SAMP8 mice. Contrastingly, Tranilast administration increased the HHWT in aged, but not young SAMP8 mice. These results suggest that the modulation of heat pain sensitivity in the oral mucosa due to aging is dependent on changes in the TRPV1 and TRPV2 expression patterns in the TG neurons innervating the palatal mucosa.