Specific intraspinal projection patterns of lumbar commissural axons in cats

• Matsuyama Kiyoji

  Dept. Physiol., Sapporo Med. Univ. Schl. Med., Sapporo, Japan

• Kobayashi Suguru

  Dept. Physiol., Sapporo Med. Univ. Schl. Med., Sapporo, Japan

• Aoki Mamoru

  Dept. Physiol., Sapporo Med. Univ. Schl. Med., Sapporo, Japan

Bibliographic Information

Other Title

• ネコ腰髄交連軸索の形態的分化に基づく脊髄内投射様式の特異性

Abstract

Commissural neurons (CNs) mutually connecting the bilateral spinal cord (SC) are essential neural elements for generating the reciprocal left-right locomotor rhythm. To know characteristics of such mutual connections, we analyzed the projection patterns of single CN axons in the cat lumbar SC with a neural tracing technique using biotinylated-dextran amine (BDA). A small volume of BDA (5-10 nl, 20%) was focally injected into lamina VIII at L5-6 segments. After 2-4 weeks, animals were perfused and fixed, and serial transverse 50 μm sections of L1-S2 segments were made. To visualize BDA labelings, they were processed according to ABC/DAB procedure. At the injection level, many labeled CN axons crossed the midline to the opposite ventral funiculus. Then, they ascended rostrally and/or descended caudally, giving off multiple axon collaterals. Trajectories of single CN axons were traced in continuity from serial sections, and their collateral branching was reconstructed. Although each branching pattern of individual CN axons varied, the axons we identified could be clearly divided into 2 major groups according to their innervation areas. Axon collaterals from the first group always innervated laminae VIII-VII (interneuronal nuclei), whereas those from the second one innervated lamina IX (motor nuclei). Further, axon collaterals arising from a given CN axon in both groups commonly terminated in similar regions at all SC levels along the course of that axon. These findings suggest that the morphology of each CN axon is differentiated in a specific fashion so as to meet its functional role necessitated. [Jpn J Physiol 55 Suppl:S174 (2005)]

Journal

• Proceedings of Annual Meeting of the Physiological Society of Japan

  Proceedings of Annual Meeting of the Physiological Society of Japan 2005 (0), S174-S174, 2005

  PHYSIOLOGICAL SOCIETY OF JAPAN

Keywords

• commissural axon
• axonal differentiation
• spinal cord
• cat
• locomotion

Details

• CRID: 1390282680705193984
• NII Article ID: 130005447699
• DOI: 10.14849/psjproc.2005.0_s174_2
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed