Ultrastructural study of the primary olfactory pathway in Macaca fascicularis

Loren P. Herrera, Carlos E. Casas, Margaret L. Bates, James D. Guest

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Olfactory ensheathing glial cells (OEGs) interact with a wide repertoire of cell types and support extension of olfactory axons (OAs) within the olfactory pathway. OEGs are thought to exclude OAs from contact with all other cells between the olfactory epithelium and the glomerulus of the olfactory bulb. These properties have lead to testing to determine whether OEGs support axonal growth following transplantation. The cellular interactions of transplanted OEGs will probably resemble those that occur within the normal pathway where interactions between OEGs and fibroblasts are prominent. No previous primate studies have focused on these interactions, knowledge of which is important if clinical application is envisioned. We describe the detailed intercellular interactions of OAs with supporting cells throughout the olfactory epithelium, the lamina propria, the fila olfactoria, and the olfactory nerve layer by using transmission electron microscopy in adult Macaca fascicularis. Patterns of OEG ensheathment and variations of the endo- and perineurium formed by olfactory nerve fibroblasts are described. OAs mainly interacted with horizontal basal cells, OEGs, and astrocytes. At both transitional ends of the pathway seamless intercellular interactions were observed, and fibroblast processes were absent. Perineurial cells produced surface basal lamina; however, endoneurial, epineurial, and meningeal fibroblasts did not. Perineurial cells contained intermediate filaments and were distinct from other fibroblasts and meningeal cells. OAs had direct contacts with astrocytes near fheglia limitans. The properties of OEGs differed depending on whether astrocytic or fibroblastic processes were present. This indicates the importance of the cellular milieu in the structure and function of OEGs in primates.

Original languageEnglish (US)
Pages (from-to)427-441
Number of pages15
JournalJournal of Comparative Neurology
Issue number4
StatePublished - Aug 8 2005


  • Astrocytes
  • Fibroblasts
  • Fila olfactoria
  • Lamina propria
  • Non-human primates
  • Olfactory bulb
  • Olfactory ensheathing cells
  • Perineurium
  • Schwann cells
  • Ultrastructure

ASJC Scopus subject areas

  • Neuroscience(all)


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