Distribution of tyrosine hydroxylase- and serotonin-immunoreactive cells in the central nervous system of the thornback guitarfish, Platyrhinoidis triseriata.

Distribution of tyrosine hydroxylase- and serotonin-immunoreactive cells in the central nervous system of the thornback guitarfish, Platyrhinoidis triseriata.

Stuesse S L; Cruce W L; Northcutt R G

Journal of chemical neuroanatomy

1990

1990-02

Brainstem reticular nuclei of amniotes (mammals, birds and reptiles) may share a common phylogenetic origin as demonstrated by their many shared features (hodology, cytoarchitectonics, presence of neurochemicals). By studying characteristics of these nuclei in outgroups of amniotes, we hope to obtain clues about the phylogeny of the reticular formation. In this paper we report the distribution of immunoreactivity to tyrosine hydroxylase (TH) and serotonin (5-HT) in the brain of an elasmobranch, the thornback guitarfish, Platyrhinoidis triseriata. Our working hypothesis is that if morphologically and immunohistochemically similar cell groups are present, they are homologous to cell groups in amniotes. Thus we have used mammalian terminology. The dorsal and lateral pallium of the telencephalon and many diencephalic nuclei contained TH+ cells. In the mesencephalon, TH+ cell groups were located in raphe linearis, the ventral tegmentum and substantia nigra. The rhombencephalon contained TH+ cells in a putative locus coeruleus (A6), and a subcoeruleus group. Probable A5, A2/C2 and A1/C1 groups were also located. A few 5-HT+ cells were located in the telencephalon and many were found in the diencephalon. In the mesencephalon,

Animals; Immunohistochemistry; Tyrosine 3-Monooxygenase/*metabolism; Serotonin/*metabolism; Fishes/*metabolism; Central Nervous System/cytology/*metabolism

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