Neurogenic period of ascending tract neurons in the upper lumbar spinal cord of the rat

Journal Article · Thu Feb 01 04:00:00 EST 1990 · Experimental Neurology; (USA)

DOI:https://doi.org/10.1016/0014-4886(90)90157-N· OSTI ID:6993157

Nandi, K N; Beal, J A; Knight, D S ^[1]

---

1. Louisiana State Univ. Medical Center, Shreveport (USA)

Although the neurogenic period for neurons in the lumbar spinal cord has been clearly established (Days 12 through 16 of gestation), it is not known when the neurogenesis of ascending tract neurons is completed within this period. The purpose of the present study was to determine the duration of the neurogenic period for projection neurons of the ascending tracts. To label neurons undergoing mitosis during this period, tritiated thymidine was administered to fetal rats on Embryonic (E) Days E13 through E16 of gestation. Ascending tract neurons of the lumbar cord were later (Postnatal Days 40-50) labeled in each animal with a retrograde tracer, Fluoro-Gold, applied at the site of a hemisection at spinal cord segment C3. Ascending tract neurons which were undergoing mitosis in the upper lumbar cord were double labeled, i.e., labeled with both tritiated thymidine and Fluoro-Gold. On Day E13, 89-92% of the ascending tract neurons were double labeled; on Day E14, 35-37%; and on Day E15, 1-4%. Results showed, then, that some ascending tract neurons were double labeled through Day E15 and were, therefore, proliferating in the final one-third of the neurogenic period. Ascending tract neurons proliferating on Day E15 were confined to laminae III, IV, V, and X and the nucleus dorsalis. Long tract neurons in the superficial dorsal horn (laminae I and II), on the other hand, were found to have completed neurogenesis on Day E14 of gestation. Results of the present study show that spinal neurogenesis of ascending projection neurons continues throughout most of the neurogenic period and does not completely follow the well-established ventral to dorsal gradient.

• OSTI ID: 6993157
• Journal Information: Experimental Neurology; (USA), Journal Name: Experimental Neurology; (USA) Vol. 107:2; ISSN 0014-4886; ISSN EXNEA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
AZINES
CELL DIVISION
CELL PROLIFERATION
CENTRAL NERVOUS SYSTEM
DOUBLE LABELLING
FETUSES
FLUORESCENCE
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LABELLING
LUMINESCENCE
MAMMALS
MITOSIS
NERVE CELLS
NERVOUS SYSTEM
NUCLEOSIDES
NUCLEOTIDES
ONTOGENESIS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYSIOLOGY
PYRIMIDINES
RATS
RIBOSIDES
RODENTS
SOMATIC CELLS
SPINAL CORD
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES