Raphe nuclei in three cartilaginous fishes, Hydrolagus colliei, Heterodontus francisci, and Squalus acanthias.

Title

Raphe nuclei in three cartilaginous fishes, Hydrolagus colliei, Heterodontus francisci, and Squalus acanthias.

Creator

Stuesse S L; Stuesse D C; Cruce W L

Publisher

The Journal of comparative neurology

Date

1995
1995-07

Description

The vertebrate reticular formation, containing over 30 nuclei in mammals, is a core brainstem area with a long evolutionary history. However, not all reticular nuclei are equally old. Nuclei that are widespread among the vertebrate classes are probably ones that evolved early. We describe raphe nuclei in the reticular formation of three cartilaginous fishes that diverged from a common ancestor over 350 million years ago. These fishes are Hydrolagus colliei, a holocephalan, Squalus acanthias, a small-brained shark, and Heterodontus francisci, a large-brained shark. Nuclear identification was based on immunohistochemical localization of serotonin and leu-enkephalin, on brainstem location, and on cytoarchitectonics. Raphe nuclei are clustered in inferior and superior cell groups, but within these groups individual nuclei can be identified: raphe pallidus, raphe obscurus, and raphe magnus in the inferior group and raphe pontis, raphe dorsalis, raphe centralis superior, and raphe linearis in the superior group. Hydrolagus lacked a dorsal raphe nucleus, but the nucleus was present in the sharks. The majority of immunoreactive cells are found in the superior group, especially in raphe centralis superior, but immunoreactive cells are present from spinal cord to caudal mesencephalon. The distribution and cytoarchitectonics of serotoninergic and enkephalinergic cells are similar to each other, but raphe nuclei contain fewer enkephalinergic than serotoninergic cells. The cytoarchitectonics of immunoreactive raphe cells in cartilaginous fishes are remarkably similar to those described for raphe nuclei in mammals; however, the lack of a raphe dorsalis in Hydrolagus indicates that either it evolved later than the other raphe nuclei or it was lost in holocephalan fishes.

Subject

*Biological Evolution; Animals; Dogfish/*anatomy & histology/metabolism; Elasmobranchii/*anatomy & histology/metabolism; Enkephalin; Immunohistochemistry; Leucine/analysis; Raphe Nuclei/*anatomy & histology/chemistry; Serotonin/analysis; Sharks/*anatomy & histology/metabolism

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

414–427

Issue

3

Volume

358

Citation

Stuesse S L; Stuesse D C; Cruce W L, “Raphe nuclei in three cartilaginous fishes, Hydrolagus colliei, Heterodontus francisci, and Squalus acanthias.,” NEOMED Bibliography Database, accessed October 1, 2022, https://neomed.omeka.net/items/show/2996.

Social Bookmarking