Fos-immunoreaction on the laryngeal reflex arc in the lower brainstem of cat

• Published in: jibi to rinsho Vol. 47; no. 1; pp. 22 - 31
• Main Author: FUKUNAGA, Hiroyuki
• Format: Journal Article
• Language: Japanese
• Published: JIBI TO RINSHO KAI 20.01.2001
• ISSN: 0447-7227; 2185-1034
• DOI: 10.11334/jibi1954.47.1_22

After, electrostimulation of the internal branch of the superior laryngeal nerve, the neuronal connection between the nucleus tractus solitarii (NTS) and the nucleus ambiguus (AMB) of the laryngeal reflex arc in the lower brainstem of the cat was investigated using the immunohistochemical double labeling method with cholera toxin in order to identify thyroarytenoid motoneurons, and Fos, the protein of the immediate early gene c-fos. Regarding the Fos expression, which is mainly observed in the NTS, both the reticular formation (RF) and the AMB, were counted under a microscope. The number of Fosimmunoreactive neurons was langer in the NTS than in the RF and the AMB, in that order. In the NTS, the number of Fos-reactive neurons on the stimulated side was significantly larger than that on the unstimulated side. These findings suggest that less than three inter neurons exist between the NTS and AMB in a reflective glottic closure with a latency of less than 9 msec after electric stimulation. From the NTS, the neuronal pathways of a direct connection to the bilateral AMB, the projections to the AMB via the contralateral NTS, and the neural connection to the AMB through the ipsi and contra lateral RF were all clearly demonstrated, and they might therefore also participate as several routes in the laryngeal reflex.