Serotonergic modulation of the respiratory rhythm generator at birth: an in vitro study in the rat

Neurosci Lett. 1992 Aug 31;143(1-2):91-5. doi: 10.1016/0304-3940(92)90240-8.


In order to investigate the mechanisms through which serotonin (5-HT) modulates the activity of the respiratory rhythm generator, respiratory activity was recorded from cervical ventral roots of the superfused isolated brainstem-spinal cord preparation of the newborn rat. Replacing the normal bathing medium by a medium containing 5-HT (30 microM) increased the respiratory frequency by 70% of the control value. Intact pontomedullary structures are necessary for this effect to take place, however, since the 5-HT-induced increases in respiratory frequency were no longer observed after elimination (section and electrolytic lesion) of the caudal ventro-lateral pons containing the A5 areas. Local applications of 5-HT (dual bath, microdialysis and microinjection experiments) revealed, however, that 5-HT acts at the medullary level and that its effects are not due to a diffuse action on all the neurons of the medullary respiratory centers but to a specific action focusing on structures located in the rostral ventro-lateral medulla.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn / physiology*
  • Medulla Oblongata / drug effects
  • Medulla Oblongata / physiology*
  • Periodicity
  • Pons / drug effects
  • Pons / physiology*
  • Rats
  • Receptors, Serotonin / physiology
  • Respiration / physiology*
  • Respiratory Center / drug effects
  • Respiratory Center / physiology*
  • Serotonin / physiology*
  • Spinal Nerve Roots / physiology
  • Stimulation, Chemical


  • Receptors, Serotonin
  • Serotonin