Neuroscience and Behavioral Physiology

, Volume 30, Issue 4, pp 449–453

The effects of the mediodorsal nucleus of the thalamus on respiratory neurons of the medulla oblongata and respiration in rats in conditions of hypoxia

  • N. S. Akopyan
  • O. G. Baklavadzhyan
  • V. V. Sarkisyan


The effects of the associated mediodorsal nucleus of the thalamus on spike activity of respiratory neurons in the medulla oblongata and on respiration were studied in normal conditions and in oxygen insufficiency. At normal atmospheric pressure, before animals were elevated to low pressures, electrical stimulation of the mediodorsal nucleus of the thalamus had predominantly inhibitory effects. At the initial phase of hypoxia, at a “height” of 4000–5000 m, hypoxic activation of neuron discharge frequency occurred, with an increase in the frequency of respiration. In these conditions, the inhibitory effect of stimulation of the mediodorsal nucleus of the thalamus was less marked than in normoxic conditions. The opposite effect occurred at the second phase of hypoxia (7500–8000 m)— inhibition of activity in the medulla oblongata and thalamic center. In severe hypoxia, there was inhibition of neuron spike activity and a decrease in the frequency of respiration, which became superficial; in these conditions, the inhibitory effect of the thalamus was insignificant.

Key words

Normoxia mediodorsal nucleus of the thalamus expiratory and inspiratory neurons 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    N. S. Akopyan, O. G. Baklavadzhyan, and N. V. Sarkisyan, “The role of the limbic cortex in controlling the spike activity of neurons in the respiratory center of the medulla oblongata in conditions of oxygen deficiency,”Zh. Vyssh. Nerv. Deyat.,44, No. 4–5, 777–785 (1994).Google Scholar
  2. 2.
    O. G. Baklavadzhyan, L. B. Nersesyan, and N. K. Manukyan, “Responses of neurons in the bulbar respiratory center to stimulation of the anterior ventral and mediodorsal thalamic nuclei,”Neirofiziologiya,25, No. 3, 218–225 (1993).Google Scholar
  3. 3.
    Ya. Buresh, M. Petran, and I. Zakhar,Electrophysiological Study Methods [Russian translation], Foreign Literature Press (Inostrannaya Literature), Moscow (1962).Google Scholar
  4. 4.
    R. A. Durinyan,Central Structures of Afferent Systems [in Russian], Meditsina, Moscow (1965).Google Scholar
  5. 5.
    V. N. Kazakov,Integrative Mechanisms of the Thalamus. A Partial Physiology of the Nervous System [in Russian], Nauka, Leningrad (1983).Google Scholar
  6. 6.
    A. G. Kartseva, N. Z. Vasil'eva, and V. V. Raevskii, “Studies of descending pathways of suprabulbar structures of the cat brain, involved in controlling the circulation,” in:Axonal Transport of Substances in Brain Systems [in Russian], Kiev (1981).Google Scholar
  7. 7.
    T. A. Leontovich,Neuronal Organization of Subcortical Formations of the Forebrain [Russian translation], Forergn Literature Press (Inostrannaya Literatura) Moscow (1962).Google Scholar
  8. 8.
    L. B. Nersesyan, “Effects of the limaic system and hypothalamus on the activity of medullary neurons,”Fiziol. Zh. SSSR,71, No. 3, 304–309 (1985).Google Scholar
  9. 9.
    I. Oivin, “Statistical processing of experimental data,”Zh. Patol. Éksper. Terapii,4, No. 4, 76–85 (1959).Google Scholar
  10. 10.
    F. N. Serkov and V. N. Kazakov,Neurophysiology of the Thalamus [in Russian], Naukova Dumka, Kiev (1980).Google Scholar
  11. 11.
    K. E. Livingston and A. Escobar, “Anatomical basis of the systems concept,”Arch. Neurol.,24, No. 1, 17–21 (1971).PubMedGoogle Scholar
  12. 12.
    R. R. Terreberry and E. J. Neafsey, “Rat medial frontal cortex visceral motor region with a direct projection to the solitary tract,”Brain Res.,178, No. 1, 245–249 (1983).CrossRefGoogle Scholar

Copyright information

© Kluwer Academic/Plenum Publishers 2000

Authors and Affiliations

  • N. S. Akopyan
  • O. G. Baklavadzhyan
  • V. V. Sarkisyan
    • 1
  1. 1.Department of Human and Animal PhysiologyErevan State UniversityErevanArmenia

Personalised recommendations