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. 1988 Feb;93(2):257–266. doi: 10.1111/j.1476-5381.1988.tb11429.x

The effect of dantrolene sodium on the discharge of alpha and gamma motoneurones to the soleus muscle in the decerebrate rat.

R Farquhar 1, N J Part 1
PMCID: PMC1853791  PMID: 3359105

Abstract

1. The effects of intravenous infusion of the direct acting muscle relaxant, dantrolene sodium (5 mg kg-1), on tension, integrated EMG, soleus muscle motor unit discharge frequency and gamma nerve fibre discharge were measured in the decerebrate rat. 2. Dantrolene sodium did not have any detectable direct effect upon the discharge of the gamma nerve fibres. 3. The soleus muscle of the decerebrate preparations exhibited spontaneous tension and reflex responses. 4. With the muscle held at constant length, dantrolene sodium caused an increase in the integrated EMG in 15 out of 18 experiments and a decrease in muscle tension in 15 out of 17. The results from these experiments showed great variability. 5. Dantrolene sodium caused a slight reduction in the tension response to tonic stretch; this was accompanied by an increase in the integrated EMG. 6. Dantrolene sodium also caused a shift in the relationship between tension and integrated EMG during the phasic component of the stretch reflex, with a greater integrated EMG being associated with a reduced tension. 7. Motor unit discharge frequencies were found to increase but not sufficiently to overcome the action of dantrolene sodium. It is concluded that motor unit recruitment must play an important role in the compensation for the muscle weakening action of dantrolene sodium.

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Selected References

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

  1. Andrew B. L., Leslie G. C., Part N. J. Some observations on the efferent innervation of rat soleus muscle spindles. Exp Brain Res. 1978 Mar 15;31(3):433–443. doi: 10.1007/BF00237300. [DOI] [PubMed] [Google Scholar]
  2. Andrew B. L., Part N. J. Properties of fast and slow motor units in hind limb and tail muscles of the rat. Q J Exp Physiol Cogn Med Sci. 1972 Apr;57(2):213–225. doi: 10.1113/expphysiol.1972.sp002151. [DOI] [PubMed] [Google Scholar]
  3. Bowman W. C., Houston J., Khan H. H., Rodger I. W. Effects of dantrolene sodium on respiratory and other muscles and on respiratory parameters in the anaesthetised cat. Eur J Pharmacol. 1979 May 1;55(3):293–303. doi: 10.1016/0014-2999(79)90197-3. [DOI] [PubMed] [Google Scholar]
  4. Ellaway P. H., Trott J. R. Autogenetic reflex action on to gamma motoneurones by stretch of triceps surae in the decerebrated cat. J Physiol. 1978 Mar;276:49–66. doi: 10.1113/jphysiol.1978.sp012219. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Ellis K. O., Bryant S. H. Excitation-contraction uncoupling in skeletal muscle by dantrolene sodium. Naunyn Schmiedebergs Arch Pharmacol. 1972;274(1):107–109. doi: 10.1007/BF00501011. [DOI] [PubMed] [Google Scholar]
  6. Ellis K. O., Wessels F. L., Carpenter J. F. Effects of intravenous dantrolene sodium on respiratory and cardiovascular functions. J Pharm Sci. 1976 Sep;65(9):1359–1364. doi: 10.1002/jps.2600650925. [DOI] [PubMed] [Google Scholar]
  7. Farquhar R., Leslie G. C., Part N. J. How is ventilation maintained in the presence of the muscle relaxant, dantrolene sodium? A study in the anaesthetized rat. Br J Pharmacol. 1986 May;88(1):79–86. doi: 10.1111/j.1476-5381.1986.tb09473.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Knutsson E., Martensson A. Action of dantrolene sodium in spasticity with low dependence on fusimotor drive. J Neurol Sci. 1976 Oct;29(2-4):195–212. doi: 10.1016/0022-510x(76)90171-4. [DOI] [PubMed] [Google Scholar]
  9. Leslie G. C., Part N. J. The action of dantrolene sodium on individual fast and slow motor units of the rat anaesthetized with urethane. Br J Pharmacol. 1984 Feb;81(2):351–360. doi: 10.1111/j.1476-5381.1984.tb10086.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Leslie G. C., Part N. J. The effect of dantrolene sodium on intrafusal muscle fibres in the rat soleus muscle. J Physiol. 1981 Sep;318:73–83. doi: 10.1113/jphysiol.1981.sp013851. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Mai J., Pedersen E. Mode of action of dantrolene sodium in spasticity. Acta Neurol Scand. 1979 Jun;59(6):309–316. doi: 10.1111/j.1600-0404.1979.tb02941.x. [DOI] [PubMed] [Google Scholar]
  12. Mendell L. M., Henneman E. Terminals of single Ia fibers: distribution within a pool of 300 homonymous motor neurons. Science. 1968 Apr 5;160(3823):96–98. doi: 10.1126/science.160.3823.96. [DOI] [PubMed] [Google Scholar]
  13. Monster A. W., Herman R., Meeks S., McHenry J. Cooperative study for assessing the effects of a pharmacological agent on spasticity. Am J Phys Med. 1973 Aug;52(4):163–188. [PubMed] [Google Scholar]
  14. Reinking R. M., Stuart D. G. Servo-regulated electromagnetic system for muscle stretch and vibration. Am J Phys Med. 1974 Feb;53(1):1–28. [PubMed] [Google Scholar]

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