Prolonged sojourn of developing pyramidal cells in the intermediate zone of the hippocampus and their settling in the stratum pyramidale

Journal Article · Thu Nov 15 04:00:00 EST 1990 · Journal of Comparative Neurology; (USA)

DOI:https://doi.org/10.1002/cne.903010303· OSTI ID:5988290

Altman, J; Bayer, S A ^[1]

---

1. Purdue Univ., West Lafayette, IN (USA)

In radiograms of rat embryos that received a single dose of (3H)thymidine between days E16 and E20 and were killed 24 hours after the injection, the heavily labeled cells (those that ceased to multiply soon after the injection) form a horizontal layer in the intermediate zone of the hippocampus, called the inferior band. The fate of these heavily labeled cells was traced in radiograms of the dorsal hippocampus in embryos that received (3H)thymidine on day E18 and were killed at different intervals thereafter. Two hours after injection the labeled proliferative cells are located in the Ammonic neuroepithelium. The heavily labeled cells that leave the neuroepithelium and aggregate in the inferior band 1 day after the injection become progressively displaced toward the stratum pyramidale 2-3 days later, and penetrate the stratum pyramidale of the CA1 region on the 4th day. In the stratum pyramidale of the CA3 region, farther removed from the Ammonic neuroepithelium, the heavily labeled cells are still sojourning in the intermediate zone 4 days after labeling. Observations in methacrylate sections suggest that two morphogenetic features of the developing hippocampus may contribute to the long sojourn of young pyramidal cells in the intermediate zone: the way in which the stratum pyramidale forms and the way in which the alveolar channels develop. The stratum pyramidale of the CA1 region forms before that of the CA3 region, which is the reverse of the neurogenetic gradient in the production of pyramidal cells. We hypothesize that this is so because the pyramidal cells destined to settle in the CA3 region, which will be contacted by granule cells axons (the mossy fibers), have to await the formation of the granular layer on days E21-E22.

• OSTI ID: 5988290
• Journal Information: Journal of Comparative Neurology; (USA), Journal Name: Journal of Comparative Neurology; (USA) Vol. 301:3; ISSN 0021-9967; ISSN JCNEA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
AUTORADIOGRAPHY
AZINES
BODY
BRAIN
CELL PROLIFERATION
CENTRAL NERVOUS SYSTEM
EMBRYOS
EPITHELIUM
HETEROCYCLIC COMPOUNDS
HIPPOCAMPUS
HYDROGEN COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NUCLEOSIDES
NUCLEOTIDES
ONTOGENESIS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PYRIMIDINES
RATS
RIBOSIDES
RODENTS
THYMIDINE
TISSUES
TRITIUM COMPOUNDS
VERTEBRATES