Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1980 Jan;298:539–556. doi: 10.1113/jphysiol.1980.sp013100

Post-synaptic conductance increase associated with presynaptic inhibition in cat lumbar motoneurones.

P L Carlen, R Werman, Y Yaari
PMCID: PMC1279135  PMID: 7359439

Abstract

1. Motoneurones were examined in which low-intensity p.b.s.t conditioning volleys caused a 5% or greater decrease of gastrocnemius monosynaptic e.p.s.p.s without evidence of long-lasting i.p.s.p.s on superimposed single sweeps. 2. Short constant current pulses were injected into these cells and in twenty-two of twenty-three cases the voltage decay was faster when preceded by the same p.b.s.t. conditioning stimuli which caused a decrease in the Ia e.p.s.p. 3. Comparing these decays to short pulse decays generated in a simple analogue neurone model suggested that after conditioning stimuli a tonic conductance increase had occurred which was located electrotonically remote from the soma in some cases or more diffusely in other cases. 4. Long-lasting i.p.s.p.s were brought out by averaging the baseline following conditioning stimuli in ten of fifteen cases, also suggesting a post-synaptic conductance increase. 5. Averaging the voltage response to long saturating constant current pulses showed a decreased motoneurone input resistance in three of eight cases. 6. The semilogarithmic decay of four of eleven conditioned e.p.s.p.s was more rapid than controls. 7. Although short pulse voltage decay analysis revealed consistent evidence for increased post-synaptic conductance following conditioning stimuli, it was not possible to decide if the location and extent of this conductance increase were sufficient to rule out presynaptic inhibition.

Full text

PDF
539

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Atwood H. L. Organization and synaptic physiology of crustacean neuromuscular systems. Prog Neurobiol. 1976;7(Pt 4):291–391. doi: 10.1016/0301-0082(76)90009-5. [DOI] [PubMed] [Google Scholar]
  2. Barker J. L., Nicoll R. A. The pharmacology and ionic dependency of amino acid responses in the frog spinal cord. J Physiol. 1973 Jan;228(2):259–277. doi: 10.1113/jphysiol.1973.sp010085. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Barrett J. N., Crill W. E. Specific membrane properties of cat motoneurones. J Physiol. 1974 Jun;239(2):301–324. doi: 10.1113/jphysiol.1974.sp010570. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. CURTIS D. R., PHILLIS J. W., WATKINS J. C. The depression of spinal neurones by gamma-amino-n-butyric acid and beta-alanine. J Physiol. 1959 Apr 23;146(1):185–203. doi: 10.1113/jphysiol.1959.sp006188. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cook W. A., Jr, Cangiano A. Presynaptic and postsynaptic inhibition of spinal motoneurons. J Neurophysiol. 1972 May;35(3):389–403. doi: 10.1152/jn.1972.35.3.389. [DOI] [PubMed] [Google Scholar]
  6. DUDEL J., KUFFLER S. W. Presynaptic inhibition at the crayfish neuromuscular junction. J Physiol. 1961 Mar;155:543–562. doi: 10.1113/jphysiol.1961.sp006646. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Davidoff R. A. Gamma-aminobutyric acid antagonism and presynaptic inhibition in the frog spinal cord. Science. 1972 Jan 21;175(4019):331–333. doi: 10.1126/science.175.4019.331. [DOI] [PubMed] [Google Scholar]
  8. Davidoff R. A., Graham L. T., Jr, Shank R. P., Werman R., Aprison M. H. Changes in amino acid concentrations associated with loss of spinal interneurons. J Neurochem. 1967 Oct;14(10):1025–1031. doi: 10.1111/j.1471-4159.1967.tb09513.x. [DOI] [PubMed] [Google Scholar]
  9. ECCLES J. C., ECCLES R. M., MAGNI F. Central inhibitory action attributable to presynaptic depolarization produced by muscle afferent volleys. J Physiol. 1961 Nov;159:147–166. doi: 10.1113/jphysiol.1961.sp006798. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. ECCLES J. C., SCHMIDT R., WILLIS W. D. PHARMACOLOGICAL STUDIES ON PRESYNAPTIC INHIBITION. J Physiol. 1963 Oct;168:500–530. doi: 10.1113/jphysiol.1963.sp007205. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Edwards F. R., Hirst G. D., Silinsky E. M. Interaction between inhibitory and excitatory synaptic potentials at a peripheral neurone. J Physiol. 1976 Aug;259(3):647–663. doi: 10.1113/jphysiol.1976.sp011487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Edwards F. R., Redman S. J., Walmsley B. Non-quantal fluctuations and transmission failures in charge transfer at Ia synapses on spinal motoneurones. J Physiol. 1976 Aug;259(3):689–704. doi: 10.1113/jphysiol.1976.sp011489. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Edwards F. R., Redman S. J., Walmsley B. Statistical fluctuations in charge transfer at Ia synapses on spinal motoneurones. J Physiol. 1976 Aug;259(3):665–688. doi: 10.1113/jphysiol.1976.sp011488. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Edwards F. R., Redman S. J., Walmsley B. The effect of polarizing currents on unitary Ia excitatory post-synaptic potentials evoked in spinal motoneurones. J Physiol. 1976 Aug;259(3):705–723. doi: 10.1113/jphysiol.1976.sp011490. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. GRAY E. G. A morphological basis for pre-synaptic inhibition? Nature. 1962 Jan 6;193:82–83. doi: 10.1038/193082a0. [DOI] [PubMed] [Google Scholar]
  16. Iansek R., Redman S. J. An analysis of the cable properties of spinal motoneurones using a brief intracellular current pulse. J Physiol. 1973 Nov;234(3):613–636. doi: 10.1113/jphysiol.1973.sp010364. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Jack J. J., Redman S. J. An electrical description of the motoneurone, and its application to the analysis of synaptic potentials. J Physiol. 1971 Jun;215(2):321–352. doi: 10.1113/jphysiol.1971.sp009473. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Jack J. J., Redman S. J. The propagation of transient potentials in some linear cable structures. J Physiol. 1971 Jun;215(2):283–320. doi: 10.1113/jphysiol.1971.sp009472. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Kellerth J. O., Szumski A. J. Effects of picrotoxin on stretch-activated post-synaptic inhibitions in spinal motoneurones. Acta Physiol Scand. 1966 Jan-Feb;66(1):146–156. doi: 10.1111/j.1748-1716.1966.tb03179.x. [DOI] [PubMed] [Google Scholar]
  20. Krnjević K., Puil E., Werman R. GABA and glycine actions on spinal motoneurons. Can J Physiol Pharmacol. 1977 Jun;55(3):658–669. doi: 10.1139/y77-090. [DOI] [PubMed] [Google Scholar]
  21. McLaughlin B. J. Dorsal root projections to the motor nuclei in the cat spinal cord. J Comp Neurol. 1972 Apr;144(4):461–474. doi: 10.1002/cne.901440405. [DOI] [PubMed] [Google Scholar]
  22. Nelson P. G., Lux H. D. Some electrical measurements of motoneuron parameters. Biophys J. 1970 Jan;10(1):55–73. doi: 10.1016/S0006-3495(70)86285-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. RALL W. Branching dendritic trees and motoneuron membrane resistivity. Exp Neurol. 1959 Nov;1:491–527. doi: 10.1016/0014-4886(59)90046-9. [DOI] [PubMed] [Google Scholar]
  24. RALL W. Membrane potential transients and membrane time constant of motoneurons. Exp Neurol. 1960 Oct;2:503–532. doi: 10.1016/0014-4886(60)90029-7. [DOI] [PubMed] [Google Scholar]
  25. Rall W. Distinguishing theoretical synaptic potentials computed for different soma-dendritic distributions of synaptic input. J Neurophysiol. 1967 Sep;30(5):1138–1168. doi: 10.1152/jn.1967.30.5.1138. [DOI] [PubMed] [Google Scholar]
  26. Rall W. Time constants and electrotonic length of membrane cylinders and neurons. Biophys J. 1969 Dec;9(12):1483–1508. doi: 10.1016/S0006-3495(69)86467-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Richter D. W., Schlue W. R., Mauritz K. H., Nacimiento A. C. Comparison of membrane properties of the cell body and the initial part of the axon of phasic motoneurones in the spinal cord of the cat. Exp Brain Res. 1974;20(2):193–206. doi: 10.1007/BF00234013. [DOI] [PubMed] [Google Scholar]
  28. Rudomin P., Burke R. E., Núez R., Madrid J., Dutton H. Control by Preynaptic Correlation: a mechanism affecting information transmission from Ia fibers to motoneurons. J Neurophysiol. 1975 Mar;38(2):267–284. doi: 10.1152/jn.1975.38.2.267. [DOI] [PubMed] [Google Scholar]
  29. Rudomín P., Núez R., Madrid J. Modulation of synaptic effectiveness of Ia and descending fibers in cat spinal cord. J Neurophysiol. 1975 Sep;38(5):1181–1195. doi: 10.1152/jn.1975.38.5.1181. [DOI] [PubMed] [Google Scholar]
  30. Schmidt R. F. Presynaptic inhibition in the vertebrate central nervous system. Ergeb Physiol. 1971;63:20–101. doi: 10.1007/BFb0047741. [DOI] [PubMed] [Google Scholar]
  31. Smith T. G., Wuerker R. B., Frank K. Membrane impedance changes during synaptic transmission in cat spinal motoneurons. J Neurophysiol. 1967 Sep;30(5):1072–1096. doi: 10.1152/jn.1967.30.5.1072. [DOI] [PubMed] [Google Scholar]
  32. Tebecis A. K., Phillis J. W. The use of convulsants in studying possible functions of amino acids in the toad spinal cord. Comp Biochem Physiol. 1969 Mar;28(3):1303–1315. doi: 10.1016/0010-406x(69)90568-4. [DOI] [PubMed] [Google Scholar]
  33. Tsukahara N., Murakami F., Hultborn H. Electrical constants of neurons of the red nucleus. Exp Brain Res. 1975 Jul 11;23(1):49–64. doi: 10.1007/BF00238728. [DOI] [PubMed] [Google Scholar]
  34. Werman R., Carlen P. L. Unusual behavior of the La EPSP in cat spinal motoneurons. Brain Res. 1976 Aug 13;112(2):395–401. doi: 10.1016/0006-8993(76)90294-8. [DOI] [PubMed] [Google Scholar]
  35. Werman R., Davidoff R. A., Aprison M. H. Inhibitory of glycine on spinal neurons in the cat. J Neurophysiol. 1968 Jan;31(1):81–95. doi: 10.1152/jn.1968.31.1.81. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES