Labeling of vagal motoneurons and central afferents after injection of cholera toxin B into the airway lumen

J. Julio Pérez Fontán, Christine R. Velloff

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


We tested the hypothesis that application of the subunit B of cholera toxin (CTB) to the airway mucosa would produce labeling of neuronal somata and sensory fibers in the medulla oblongata. Using 125I-CTB as a tracer, we demonstrated first that CTB is transported across the tracheal epithelium, but once in the airway wall, it remains confined to the subepithelial space and lamina propria. Despite the rarity of intrinsic neurons in these areas, intraluminal CTB labeled ≈ 10-60 neurons/rat in the nucleus ambiguus and a smaller number of neurons in the dorsal motor nucleus of the vagus. Well-defined sensory fiber terminals were also labeled in the commissural, medial, and ventrolateral subnuclei of the nucleus of the tractus solitarius. Approximately 50 and 90% of the neurons labeled by intraluminal CTB were also labeled by injections of FluoroGold into the tracheal adventitia and lung parenchyma, respectively. These findings demonstrate that a substantial number of medullary vagal motoneurons innervate targets in the vicinity of the airway epithelium. These neurons do not appear to be segregated anatomically from vagal motoneurons that project to deeper layers of the airway wall or lung parenchyma.

Original languageEnglish (US)
Pages (from-to)L152-L164
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number1 24-1
StatePublished - Jan 2001


  • Airway epithelium
  • Airway ganglia
  • Parasympathetic system
  • Retrograde neuronal markers

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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