Alpha-7 and alpha-4 nicotinic receptor subunit immunoreactivity in genioglossus muscle motoneurons

Ozra Dehkordi, Richard M. Millis, Gary C. Dennis, Bernell R. Coleman, Sheree M. Johnson, Loubat Changizi, C. Ovid Trouth

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


In the present study, immunohistochemistry combined with retrograde labeling techniques were used to determine if hypoglossal motoneurons (HMNs), retrogradely labeled after cholera toxin B subunit (CTB) injection to the genioglossus muscle in rats, show immunoreactivity for alpha-7 and alpha-4 subunits of nicotinic acetylcholine receptors (nAChRs). CTB-positive HMNs projecting to the genioglossus muscle were consistently labeled throughout the rostrocaudal extent of the hypoglossal nuclei with the greatest labeling at and caudal to area postrema. Alpha-7 subunit immunoreactivity was found in 39.44 ± 5.10% of 870 CTB-labeled motoneurons and the alpha-4 subunit in 51.01 ± 3.71% of 983 CTB-positive neurons. Rostrally, the number of genioglossal motoneurons demonstrating immunoreactivity for the alpha-7 subunit was 45.85 ± 10.04% compared to 34.96 ± 5.11% at and caudal to area postrema (P > 0.1). The number of genioglossal motoneurons that showed immunoreactivity for the alpha-4 subunit was 55.03 ± 4.83% at and caudal to area postrema compared to 42.98 ± 3.90% in rostral areas (P = 0.074). These results demonstrate that nAChR immunoreactivity is present in genioglossal motoneurons and suggest a role for alpha-7 and alpha-4 subunits containing nAChRs in the regulation of upper airway patency.

Original languageEnglish (US)
Pages (from-to)153-161
Number of pages9
JournalRespiratory Physiology and Neurobiology
Issue number2-3
StatePublished - Feb 2005
Externally publishedYes


  • Acetylcholine
  • Cholera toxin B subunit
  • Control of breathing
  • Genioglossus muscle
  • Hypoglossal nuclei
  • nAChRs

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Neuroscience(all)


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