Modulatory inputs to trigeminal motoneurons in rat slice preparation

大鼠切片制备中三叉神经运动神经元的调节输入

• 批准号: 09832008
• 负责人: INOUE Tomio
• 金额: $ 1.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09832008/
• 关键词: Trigeminal; Motoneuron; Protein Kinase A; In vitro; Serotonin; Protein Kinase C; Afterpotential; Calcium ion

Intracellular recordings were obtained from rat jaw-closing motoneurons (JCMINs) in slice preparations to investigate the effects of serotonin (5-HT) on the post-spike medium-duration afterhyperpolarization (mAHP) and an involvement of protein kinases in the effects.Application of 50 muM 5-HT caused membrane depolarization and increased input resistance in the most cells without affecting the mAHP, whereas not only membrane depolarization and an increase in input resistance, but also the suppression of the mAHP amplitude was induced by higher dose of 5-HT (100 or 200 muM).On the other hand, when the mAHP amplitude was increased by raising [Ca ^<2+1>]。 from 2 to 6 mM, 5-HT-induced attenuation of the mAHP amplitude was enhanced and even 50 muM 5-HT reduced the mAHP amplitude.This 5-HT-induced suppression of the mAHP could be mimicked by application of membrane-permeable cAMP analog 8-Br- cAMP, potentiated by the cAMP-specific phosphodiesterase inhibitor Ro 20-1724 and antagonized by protein kinase A (PKA) inhibitor H89.The enhancement of the mAHP attenuation induced by 50 muM 5-HT under raised [Ca ^<2+>]。 was blocked by a protein kinase C (PKC) inhibitor chelerythrine, suggesting an involvement of PKC in this enhancement.On the other hand, the attenuation of the mAHP induced by PKC activator phorbol 12-myristate 13-acetate was almost completely blocked by H89, suggesting that the PKC action on the mAHP requires PKA activation.We conclude that 5-HT induces dose-dependent attenuation of the mAHP amplitude through cAMP-dependent activation of PKA, and that PKC-dependent PKA activation is also likely to be involved in the enhancement of 5-HT-induced attenuation of the mAHP under raised [Ca^<2+>]。We also examied alteration of intracellular calcium concentration ([Ca^<2+>]). [Ca^<2+>] increased when burst firing was eliced by current injection.It is suggested that [Ca^<2+>] changes according to motoneuronal activity.

采用大鼠下颌闭合运动神经元（JCMINs）的细胞内记录方法，研究5-羟色胺（5-HT）对动作电位后中时程后超极化（mAHP）的影响及蛋白激酶的参与。50 μ M 5-HT引起大多数细胞膜去极化和输入阻力增加，但不影响mAHP，而高剂量5-HT（100或200 μ M）不仅引起膜去极化和输入电阻增加，而且抑制mAHP振幅。从2到6 mM，5-HT诱导的mAHP幅度的衰减增强，甚至50 μ M5-HT也降低mAHP幅度。这种5-HT诱导的mAHP抑制可以通过应用膜渗透性cAMP类似物8-Br-cAMP来模拟，由cAMP特异性磷酸二酯酶抑制剂Ro 20-1724增强，并由蛋白激酶A（PKA）拮抗抑制剂H89。在升高[Ca ^<2+>]条件下，50 μ M 5-HT诱导的mAHP衰减增强。被蛋白激酶C（PKC）抑制剂白屈菜红碱阻断，表明PKC参与了这种增强作用。另一方面，PKC激活剂佛波醇12-肉豆蔻酸酯13-乙酸酯诱导的mAHP衰减几乎完全被H89阻断，提示PKC对mAHP的作用需要PKA激活。我们得出结论，5-HT通过cAMP诱导mAHP振幅的剂量依赖性衰减。PKA依赖性激活，并且PKC依赖性PKA激活也可能参与5-HT诱导的mAHP在升高的[Ca^<2+>]下的衰减增强。同时观察了细胞内钙离子浓度（[Ca^<2+]）的变化。[Ca[Ca^<2+>]随电流注入诱发爆发性放电而增加，提示[Ca^<2+>]的变化与运动神经元的活动有关。

项目成果

Inoue, T.: "Effects of serotonin on spike afterpotentials in rat jaw-closing motneurons" Jpn. J. Physiol.48. S162 (1998)

Inoue, T.：“血清素对大鼠下颌闭合运动神经元尖峰后电位的影响”Jpn。

Inoue,T.: "Symposium on Neurobiology of Mastication" Elsevier Science (in press), (1999)

Inoue,T.：“咀嚼神经生物学研讨会”Elsevier Science（正在出版），（1999）

Kato, T.: "Characteristics of the muscle spindle endings of the masticatory muscles in the rabbit under halothane anesthesia." Brain Res.(in press).

Kato, T.：“氟烷麻醉下兔子咀嚼肌肌梭末端的特征。”

Inoue, T.: "Serotonergic effects on post-spike afterhyperpolarization of jaw closing motoneurons int the rat." Neurosci.Res.S22. S76 (1998)

Inoue, T.：“血清素对大鼠下颌闭合运动神经元尖峰后超极化的影响。”

Inoue, T.: "Serotonergic modulation of spike afterhyperpolarization in rat jaw-closing motoneurons." Soc.Neurosci.Abstr.24. 1105 (1998)

Inoue, T.：“大鼠下颌闭合运动神经元超极化后尖峰的血清素调节。”