Sleep and Breathing

, Volume 10, Issue 4, pp 195–202

Modulation of respiratory pattern and upper airway muscle activity by the pedunculopontine tegmentum: role of NMDA receptors

  • Jasna Saponjic
  • Miodrag Radulovacki
  • David W. Carley
Original Article

DOI: 10.1007/s11325-006-0075-9

Cite this article as:
Saponjic, J., Radulovacki, M. & Carley, D.W. Sleep Breath (2006) 10: 195. doi:10.1007/s11325-006-0075-9

Abstract

The pedunculopontine tegmental nucleus (PPT) is postulated to have important functions relevant to the regulation of rapid eye movement (REM) sleep and arousal, and various motor control systems including respiration. We have recently shown that pharmacologic activation of a neuronal subpopulation within the PPT, induced by micropipette injection of glutamate in nanoliter volumes, can produce respiratory rhythm disturbances and changes in genioglossus muscle activity in anesthetized rats. The aim of this study was to determine whether the respiratory pattern disturbance and increased genioglossus muscle tone induced by glutamate injection within the PPT are mediated by activation of N-methyl-D-aspartate (NMDA) receptors within the PPT. Experiments were performed in eight adult male spontaneously breathing Sprague-Dawley rats anesthetized using nembutal. Respiratory movements were monitored by piezoelectric strain gauge. Three-barrel glass pipettes were used to pressure inject glutamate (as a probe for respiratory modulating sites), ketamine (an NMDA channel blocker), and oil-red dye (to aid in histological verification of the injection sites) within the PPT. Electroencephalograms were recorded from the sensorimotor cortex, the hippocampus, and the pons, contralateral to the injection site. Electromyograms (EMGs) were recorded from the genioglossus muscle. The typical response to glutamate injection within the PPT respiratory-modulating region was immediate apnea followed by tachypnea and increased genioglossal tonic activity. The noncompetitive NMDA receptor channel-antagonist ketamine, injected at the same site and in the same volume as glutamate (5 nl), blocked respiratory dysrhythmia and genioglossal EMG responses to subsequent glutamate injections. For the first time, the present results suggest that respiratory rhythm and upper airway muscle tone are controlled by the activation of pedunculopontine tegmental nucleus NMDA receptors.

Keywords

Pedunculopontine tegmental nucleusRespiratory dysrhythmiaGenioglossus muscle activityGlutamateKetamineRapid eye movement sleep

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Jasna Saponjic
    • 1
    • 4
  • Miodrag Radulovacki
    • 2
  • David W. Carley
    • 1
    • 2
    • 3
  1. 1.Department of MedicineUniversity of IllinoisChicagoUSA
  2. 2.Department of PharmacologyUniversity of IllinoisChicagoUSA
  3. 3.Department of Medical-Surgical NursingUniversity of IllinoisChicagoUSA
  4. 4.Section of Pulmonary, Critical Care and Sleep MedicineDepartment of Medicine (MC 719)ChicagoUSA