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Organization of the trigeminal motor nucleus before and after metamorphosis in lampreys
| Content Provider | Semantic Scholar |
|---|---|
| Author | Homma, Shinji |
| Copyright Year | 1978 |
| Abstract | Summary During metamorphosis of the lamprey the simple muscles of the mouth of the larvae are replaced with the elaborate muscles of the sucker, rasper and pharynx in adults. The purposes of the present experiments were the identification of motoneurons to mouth muscles and the determination of their patterns in the trigeminal nucleus before and after metamorphosis. (1) Motoneurons were identified physiologically by observation of contractions in motor units following intracellular stimulation and by antidromic stimulation. Locations of motoneurons were also determined morphologically by retrograde transport of horseradish peroxidase. (2) The trigeminal motor nucleus was subdivided into regions containing motoneurons to specific groups of ipsilateral muscles both in larvae and in adults. The medial-caudal portion of the nucleus contained motoneurons innervating muscles of the oral hood in larvae and the annularis muscles of the sucker in adults. The simple ventral muscles of the larva were replaced by the elaborate muscles of the rasper and piston of adults, yet motoneurons were located in rostral portion of the nucleus in both stages. Likewise, the dissimilar muscles innervated through the basilar nerve had motoneurons in the lateral part of the nucleus in larvae and adults. The velum becomes much smaller during metamorphosis, but motoneurons innervating it in larvae and adults had the same lateral location. (3) It is concluded that the pattern of cells in the trigeminal motor nucleus is not changed during metamorphosis of the lamprey. Perhaps the same motoneurons make new peripheral connections during and after metamorphosis, or new neurons form in the same general regions of the trigeminal nucleus and innervate the new muscles forming in the corresponding regions. |
| Starting Page | 33 |
| Ending Page | 42 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0006-8993(78)90236-6 |
| PubMed reference number | 626885 |
| Journal | Medline |
| Volume Number | 140 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/0006899378902366 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/0006899378902366?dgcid=api_sd_search-api-endpoint |
| Alternate Webpage(s) | https://doi.org/10.1016/0006-8993%2878%2990236-6 |
| Journal | Brain Research |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
