Neuroscience and Behavioral Physiology

, Volume 30, Issue 4, pp 475–480 | Cite as

Inhibition of medullary reticulospinal neurons by excitation of the dorsolateral parts of the pons which block movement and muscle tone in rats

  • B. Yu. Mileikovskii
  • L. I. Kiyashchenko
  • E. S. Titkov


Analysis of the response of 128 reticulospinal neurons in the magnocellular and ventral reticular nuclei showed that 36.7% of these cells responded with short-latency (2–4 msec) action potentials and increased their tonic activity in response to electrical stimulation of the central parts of the hypothalamus, which evoked increases in hindlimb muscle tone in rats. These cells completely stopped producing action potentials during electrical stimulation and during chemical stimulation of the dorsolateral parts of the pons, which inhibited movement and muscle tone. A total of 23.4% of the cells produced only short-latency (1–4 msec) action potentials in response to stimulation of the inhibitory parts of the pons. A total of 3.9% of reticulospinal neurons increased their activity during stimulation of the hypothalamic zones and pontine areas of the brain. No responses were obtained from 35.9% of neurons. It is suggested that excitation of pontine structures inhibiting movement and muscle tone may prevent conduction in descending activatory systems from the rostral parts of the brain (which increase muscle tone) to the reticulospinal neurons of the medulla oblongata.

Key Words

Brainstem structures muscle tone reticulospinal neurons 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    A. M. Vein and K. Khekht,Human Sleep. Physiology and Pathology [in Russian], Meditsina, Moscow (1989).Google Scholar
  2. 2.
    I. G. Karmanova and G. A. Oganesyan,The Physiology and Pathology of the Sleep-Waking Cycle, Evolutionary Aspects [in Russian], Nauka, St. Petersburg (1994).Google Scholar
  3. 3.
    P. G. Kostyuk,The Structure and Function of the Descending Systems of the Spinal Cord [in Russian], Nauka, Leningrad (1973).Google Scholar
  4. 4.
    B. Yu. Mileikovskii, “The interaction of neurons in the dorsolateral part of the pons with reticulospinal cells of the medulla oblongata which inhibit the activity of hind limb alpha-motoneurons,” in:Proceedings of the Symposium “Brain Organization at the Macro- and Microlevels in Normal Conditions and Pathology [in Russian], Moscow (1992).Google Scholar
  5. 5.
    B. Yu. Mileikovskii, “The effects of stimulation of movement-inhibiting parts of the pons on neuron activity in the medial part of the medulla oblongata,”Ros. Fiziol. Zh. im. I. M. Sechenova,79, No. 7, 41–48 (1993).Google Scholar
  6. 6.
    B. Yu. Mileikovskii, S. V. Berevkina, and A. D. Nozdrechev, “Central neurophysiological mechanisms for the regulation of inhibition,”Fiziol. Zh. SSSR,76, No. 3, 289–294 (1990).PubMedGoogle Scholar
  7. 7.
    B. Yu. Mileikovskii and A. D. Nozdrachev, “Responses of neurons in the dorsolateral part of the pons in conditions of an immobilization reflex in rats,”Ros. Fiziol. Zh. im. I. M. Sechenova,83, No. 5–6, 80–93 (1997).Google Scholar
  8. 8.
    G. N. Orlovskii, “The connections of reticulospinal neurons with the ‘locomotor regions’ of the brainstem,”Biofizika,15, No. 1, 171–178 (1970).PubMedGoogle Scholar
  9. 9.
    M. L. Shik, “The locomotor region of the brainstem and the ‘locomotor column’ hypothesis,”Usp. Fiziol. Nauk.,16, No. 1, 76–95 (1985).PubMedGoogle Scholar
  10. 10.
    E. Fifkova and J. Marsala, “Stereotaxic atlases of the cat, rabbit and rat,” in:Electrophysiological Methods in Biological Research, Prague (1967).Google Scholar
  11. 11.
    K. Kawahara and M. Suzuki, “Descending inhibitory pathway responsible for simultaneous suppression of postural tone and respiration in decerebrate cat,”Brain Res.,538, No. 2, 303–309 (1991).PubMedCrossRefGoogle Scholar
  12. 12.
    F. Lopez-Rodrigues, K. A. Kohlmeier, J. Yanny, F. R. Morales, and M. H. Chase, “Muscle atonia can be induced by carbachol injections in the nucleus pontis oralis in cat anesthetized with alpha-chloralose,”Brain Res.,699, No. 2, 201–207 (1995).CrossRefGoogle Scholar
  13. 13.
    T. Oka, H. Iwakiri, and S. Mori, “Pontine-induced generalized suppression of postural muscle tone in a reflexively standing acute decerebrate cat,”Neurosci. Res.,17, No. 2, 127–140 (1993).PubMedCrossRefGoogle Scholar
  14. 14.
    T. Sakamoto, Y. Atsuta, and S. Mori, “Effects elicited by the stimulation of the dorsal part of tegmental field upon soleus alpha-motoneurons in the decerebrate standing anima,”Neurosci. Lett.,13 (Supplement), 74 (1983).Google Scholar
  15. 15.
    J. M. Siegel, R. Nienhuis, H. M. Fahringer, C. Chin, W. C. Dement, E. Mignot, and R. Lufkin, “Activity of medial mesopontine units during cataplexy and sleep-waking states in the narcoleptic dog,”J. Neurosci.,12, No. 5, 1640–1646 (1992).PubMedGoogle Scholar
  16. 16.
    K. Takakusaki, Y. Ohta, and S. Mori, “Single medullary reticulospinal neurons exert postsynaptic inhibitory effects via inhibitory interneurons upon alpha-motoneurons innervating cat hindlimb muscle,”Exp. Brain Res.,74, No. 1, 11–23 (1989).PubMedCrossRefGoogle Scholar

Copyright information

© Kluwer Academic/Plenum Publishers 2000

Authors and Affiliations

  • B. Yu. Mileikovskii
  • L. I. Kiyashchenko
  • E. S. Titkov
    • 1
  1. 1.Laboratory for the Evolution of Sleep and Waking, I. M. Sechenov Institute of Evolutionary Physiology and BiochemistryRussian Academy of SciencesSt. PetersburgRussia

Personalised recommendations