Phox2b Expressing Neurons in the Most Rostral Medulla of Newborn Rats

  • Hiroshi Onimaru
  • Keiko Ikeda
  • Kiyoshi Kawakami
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 669)


Phox2b expressing cells in the parafacial region of the ventral medulla are proposed to play a role in central chemoreception and postnatal survival. We have showed that pre-inspiratory (Pre-I) neurons in the parafacial region (pFRG/Pre-I) in neonatal rats express Phox2b and are postsynaptically CO2 sensitive. Recent evidence examining Phox2b expression established more clearly the cell architecture of the pFRG, and that Phox2b expression is the most noticeable characteristic of pFRG/Pre-I neurons. Here, we briefly review these recent findings. We also show a unique distribution of Phox2b expressing cells in the most rostral medulla, which could be an interesting target for neurophysiological analysis.


Anterior Inferior Cerebellar Artery Facial Nucleus Respiratory Neuron Rostral Ventrolateral Medulla Central Chemoreception 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Ballanyi, K., Onimaru, H., and Homma, I. (1999) Respiratory network function in the isolated brainstem-spinal cord of newborn rats. Prog. Neurobiol. 59, 583–634.CrossRefPubMedGoogle Scholar
  2. Connelly, C.A., Ellenberger, H.H., and Feldman, J.L. (1990) Respiratory activity in retrotrapezoid nucleus in cat. Am. J. Physiol. 258, L33–L44.PubMedGoogle Scholar
  3. Dubreuil, V., Ramanantsoa, N., Trochet, D., Vaubourg, V., Amiel, J., Gallego, J., Brunet, J.F., and Goridis, C. (2008) A human mutation in Phox2b causes lack of CO2 chemosensitivity, fatal central apnea, and specific loss of parafacial neurons. Proc. Natl. Acad. Sci. USA. 105, 1067-1072.CrossRefPubMedGoogle Scholar
  4. Ellenberger, H.H. and Feldman, J.L. (1990) Brainstem connections of the rostral ventral respiratory group of the rat. Brain Res. 513, 35–42.CrossRefPubMedGoogle Scholar
  5. Guyenet, P.G., Stornetta, R.L., and Bayliss, D.A. (2008) Retrotrapezoid nucleus and central chemoreception. J. Physiol. 586, 2043–2048.CrossRefPubMedGoogle Scholar
  6. Kang, B.J., Chang, D.A., Mackay, D.D., West, G.H., Moreira, T.S., Takakura, A.C., Gwilt, J.M., Guyenet, P.G., and Stornetta, R.L. (2007) Central nervous system distribution of the transcription factor Phox2b in the adult rat. J. Comp. Neurol. 503, 627–641.CrossRefPubMedGoogle Scholar
  7. Kawai, A., Onimaru, H., and Homma, I. (2006) Mechanisms of CO2/H+ chemoreception by respiratory rhythm generator neurons in the medulla from newborn rats in vitro. J. Physiol. 572, 525–537.CrossRefPubMedGoogle Scholar
  8. Nunez-Abades, P.A., Morillo, A.M., and Pasaro, R. (1993) Brainstem connections of the rat ventral respiratory subgroups: afferent projections. J. Auton. Nerv. Syst. 42, 99–118.CrossRefPubMedGoogle Scholar
  9. Onimaru, H. and Homma, I. (1992) Whole cell recordings from respiratory neurons in the medulla of brainstem-spinal cord preparations isolated from newborn rats. Pflugers Arch. 420, 399–406.CrossRefPubMedGoogle Scholar
  10. Onimaru, H. and Homma, I. (2003) A novel functional neuron group for respiratory rhythm generation in the ventral medulla. J. Neurosci. 23, 1478–1486.PubMedGoogle Scholar
  11. Onimaru, H., Ikeda, K., and Kawakami, K. (2008) CO2-sensitive preinspiratory neurons of the parafacial respiratory group express Phox2b in the neonatal rat. J. Neurosci. 28, 12845–12850.CrossRefPubMedGoogle Scholar
  12. Onimaru, H., Ikeda, K., and Kawakami, K. (2009). Phox2b, RTN/pFRG neurons and respiratory rhythmogenesis. Respir. Physiol. Neurobiol. 168, 13–18.CrossRefPubMedGoogle Scholar
  13. Pearce, R.A., Stornetta, R.L., and Guyenet, P.G. (1989). Retrotrapezoid nucleus in the rat. Neurosci. Lett. 101, 138–142.CrossRefPubMedGoogle Scholar
  14. Smith, J.C., Morrison, D.E., Ellenberger, H.H., Otto, M.R., and Feldman, J.L. (1989) Brainstem projections to the major respiratory neuron populations in the medulla of the cat. J. Comp. Neurol. 281, 69–96.CrossRefPubMedGoogle Scholar
  15. Stornetta, R.L., Moreira, T.S., Takakura, A.C., Kang, B.J., Chang, D.A., West, G.H., Brunet, J.F., Mulkey, D.K., Bayliss, D.A., and Guyenet, P.G. (2006) Expression of Phox2b by brainstem neurons involved in chemosensory integration in the adult rat. J. Neurosci. 26, 10305–10314.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Hiroshi Onimaru
    • 1
  • Keiko Ikeda
    • 2
  • Kiyoshi Kawakami
    • 2
  1. 1.Department of PhysiologyShowa University School of MedicineTokyoJapan
  2. 2.Division of Biology, Center for Molecular MedicineJichi Medical UniversityShimotsukeJapan

Personalised recommendations