孤束核与鼓索间味觉神经信号通路的实验研究

Experimental study on taste nerve signaling pathway between nucleus of the solitary tract and chorda tympani

目的探索仓鼠孤束核的味觉神经元与对侧鼓索的神经信号通路,据此为临床上单侧鼓索神经损伤的患者通常没有觉察味觉发生变化的现象提供科学解释。方法选择雄性叙利亚黄金仓鼠29只,实验记录了95个孤束核内的味觉反应神经元,检测了它们在对侧鼓索神经受到四种基本味道刺激后的反应,此外还观察了由于鼓索神经受到刺激而激活的孤束核在显微注射利多卡因后的反应。应用spike软件对味觉刺激信息和在线数据进行采集和分析。结果①通过四种基本味道刺激侧鼓索神经激活了全部95个被记录的孤束核神经元中的46个,其中42个是兴奋型反应,4个是抑制型反应。②在向对侧孤束核显微注射利多卡因后,对侧鼓索受刺激而激活孤束核神经元的过程被阻断,已经被激活的孤束核神经元的神经反应活力降低。③麻醉对侧旁核细胞,对鼓索神经受刺激后激活孤束核味觉反应神经元这一过程没有影响。结论孤束核的味觉神经元和对侧鼓索存在神经通路,并且这一神经通路可以携带味觉信息。

Objective To investigate the taste nerve signaling pathway between nucleus of the solitary tract （NST） and chorda tympani （CT）. Methods Twenty - nine young adult male Syrian golden hamsters were included. The responsiveness of 95 taste - responsive neurons in the nucleus of solitray tract was examined after the contralateral chorda tympani stimulated by four basic tastes. The activation of NST neurons by contralateral CT stimulation was also examined after microinjection of lidocaine into the contralateral NST. The control of taste stimulus delivery and online data acquisition and analysis were performed with Spike2 software. Results Stimulation of the contralateral CT activated 46 of 95 NST neurons; among them, 42 neurons were excited responses and 4 were inhibited responses. Activation of NST neurons by contralateral CT stimulation was blocked by microinjection of lidocaine into the contralateral NST. The activated NST neurons also showed reduced responsiveness to taste stimulation after microinjection of lidocaine into the contralateral NST. NST neurons responses evoked by contralateral CT stimulation were unaffected by local anesthetization of contralateral parabrachial nucleus. Conclusion The taste neurons in the NST could receive neural input from the contralateral CT nerve, it was suggested that this pathway may carry taste information. The results may clinically explain why the patients with unilateral CT nerve damage often report no subjective change in their taste experience.