Sekizawa S I, Tsubone H
Department of Comparative Pathophysiology, University of Tokyo, Japan.
Respir Physiol. 1994 Apr;96(1):37-48. doi: 10.1016/0034-5687(94)90104-x.
This study was performed to investigate the chemoreception of trigeminal afferents in the nose. Single unit activity was recorded from the anterior ethmoidal nerve in the anesthetized guinea pig breathing through a tracheostomy during nasal instillation of capsaicin (0.3 mM), nicotine (6 mM) and ammonia (1.5 M) solutions or with distilled water. Out of 36 fibers recorded, nineteen were stimulated by capsaicin, six by nicotine and seventeen by ammonia. Among those fibers, two were stimulated by both capsaicin and nicotine, six by both capsaicin and ammonia and one nicotine-responsive fiber was also stimulated by ammonia. A large proportion of capsaicin- and nicotine-responsive fibers exhibited long lasting discharges (170.4 +/- 17.7 sec and 120.7 +/- 29.3 sec, respectively), and were not stimulated by the second application of the same substance. However, fibers responding to ammonia discharged for a shorter time (31.5 +/- 6.5 sec), indicating a rapid adaptation. These results indicate that the ethmoidal nerve possesses a well-developed responsiveness to noxious stimuli. The nociceptive component of this nerve may be related to the various cardiorespiratory responses that can be elicited from the nasal cavity and also to local axonal reflexes (neurogenic inflammation) due to the release of chemical mediators from C-fiber endings.
本研究旨在调查鼻内三叉神经传入纤维的化学感受。在麻醉的豚鼠经气管切开术呼吸时，通过向鼻腔滴注辣椒素（0.3 mM）、尼古丁（6 mM）和氨（1.5 M）溶液或蒸馏水，记录筛前神经的单单位活动。在记录的36根纤维中，19根被辣椒素刺激，6根被尼古丁刺激，17根被氨刺激。在这些纤维中，2根同时被辣椒素和尼古丁刺激，6根同时被辣椒素和氨刺激，1根对尼古丁有反应的纤维也被氨刺激。大部分对辣椒素和尼古丁有反应的纤维表现出持续的放电（分别为170.4±17.7秒和120.7±29.3秒），并且在再次应用相同物质时未被刺激。然而，对氨有反应的纤维放电时间较短（31.5±6.5秒），表明其快速适应。这些结果表明筛前神经对有害刺激具有良好的反应性。该神经的伤害感受成分可能与鼻腔引发的各种心肺反应有关，也与C纤维末梢释放化学介质引起的局部轴突反射（神经源性炎症）有关。
