Skip to main content
PMC home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1972 May 1;59(5):586–615. doi: 10.1085/jgp.59.5.586

Correlated Electrophysiological and Ultrastructural Studies of a Crustacean Motor Unit

R G Sherman 1, H L Atwood 1
PMCID: PMC2203193  PMID: 5027760

Abstract

Structural and functional interrelationships between the pre- and postsynaptic elements of a singly motor innervated crab muscle (stretcher of Hyas araneus L.) were examined using electrophysiological and electron microscopic techniques. Excitatory postsynaptic potential (EPSP) amplitude at 1 Hz was found to be inversely related to the extent of facilitation, and directly related both to the amount of transmitter released at 1 Hz and the muscle fiber input resistance (R in). The extent of facilitation (Fe), taken as the ratio of the EPSP amplitude at 10 Hz to that 1 Hz, was inversely related to muscle fiber R in, τm, and sarcomere length. Sarcomere length was directly related to R in and τm. The excitatory nerve terminals of low Fe muscle fibers had larger neuromuscular synapses than did those of high Fe fibers. Inhibitory axo-axonal synapses were more often found in low Fe muscle fibers. These structural features may account for the greater release of transmitter at low frequencies from the low Fe nerve terminals as well as provide for a greater amount of presynaptic inhibition of low Fe muscle fibers. The implications of these findings for the development and physiological performance of the crustacean motor unit are discussed. It is proposed that both nerve and muscle fiber properties may be determined by the developmental pattern of nerve growth.

Full Text

The Full Text of this article is available as a PDF (2.0 MB).

Selected References

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

  1. ATWOOD H. L. DIFFERENCES IN MUSCLE FIBRE PROPERTIES AS A FACTOR IN "FAST" AND "SLOW" CONTRACTION IN CARCINUS. Comp Biochem Physiol. 1963 Sep;10:17–32. doi: 10.1016/0010-406x(63)90099-9. [DOI] [PubMed] [Google Scholar]
  2. Adrian R. H., Peachey L. D. The membrane capacity of frog twitch and slow muscle fibres. J Physiol. 1965 Nov;181(2):324–336. doi: 10.1113/jphysiol.1965.sp007764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Atwood H. L., Bittner G. D. Matching of excitatory and inhibitory inputs to crustacean muscle fibers. J Neurophysiol. 1971 Jan;34(1):157–170. doi: 10.1152/jn.1971.34.1.157. [DOI] [PubMed] [Google Scholar]
  4. Atwood H. L. Excitation and inhibition in crab muscle fibres. Comp Biochem Physiol. 1965 Dec;16(4):409–426. doi: 10.1016/0010-406x(65)90306-3. [DOI] [PubMed] [Google Scholar]
  5. Atwood H. L., Jones A. Presynaptic inhibition in crustacean muscle: axo-axonal synapse. Experientia. 1967 Dec 15;23(12):1036–1038. doi: 10.1007/BF02136434. [DOI] [PubMed] [Google Scholar]
  6. Atwood H. L., Morin W. A. Neuromuscular and axoaxonal synapses of the crayish opener muscle. J Ultrastruct Res. 1970 Aug;32(3):351–369. doi: 10.1016/s0022-5320(70)80015-6. [DOI] [PubMed] [Google Scholar]
  7. Atwood H. L. Peripheral inhibition n crustacean muscle. Experientia. 1968 Aug 15;24(8):753–763. doi: 10.1007/BF02144849. [DOI] [PubMed] [Google Scholar]
  8. BULLER A. J., ECCLES J. C., ECCLES R. M. Differentiation of fast and slow muscles in the cat hind limb. J Physiol. 1960 Feb;150:399–416. doi: 10.1113/jphysiol.1960.sp006394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. BULLER A. J., ECCLES J. C., ECCLES R. M. Interactions between motoneurones and muscles in respect of the characteristic speeds of their responses. J Physiol. 1960 Feb;150:417–439. doi: 10.1113/jphysiol.1960.sp006395. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Bittner G. D. Differentiation of nerve terminals in the crayfish opener muscle and its functional significance. J Gen Physiol. 1968 Jun;51(6):731–758. doi: 10.1085/jgp.51.6.731. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Bittner G. D., Kennedy D. Quantitative aspects of transmitter release. J Cell Biol. 1970 Dec;47(3):585–592. doi: 10.1083/jcb.47.3.585. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Burke R. E., Levine D. N., Zajac F. E., 3rd Mammalian motor units: physiological-histochemical correlation in three types in cat gastrocnemius. Science. 1971 Nov 12;174(4010):709–712. doi: 10.1126/science.174.4010.709. [DOI] [PubMed] [Google Scholar]
  13. Bárány M., Close R. I. The transformation of myosin in cross-innervated rat muscles. J Physiol. 1971 Mar;213(2):455–474. doi: 10.1113/jphysiol.1971.sp009393. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Close R. Dynamic properties of fast and slow skeletal muscles of the rat after nerve cross-union. J Physiol. 1969 Oct;204(2):331–346. doi: 10.1113/jphysiol.1969.sp008916. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Cohen M. J., Hess A. Fine structural differences in "fast" and "slow" muscle fibers of the crab. Am J Anat. 1967 Sep;121(2):285–303. doi: 10.1002/aja.1001210208. [DOI] [PubMed] [Google Scholar]
  16. DEL CASTILLO J., KATZ B. Quantal components of the end-plate potential. J Physiol. 1954 Jun 28;124(3):560–573. doi: 10.1113/jphysiol.1954.sp005129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. 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]
  18. DUDEL J., KUFFLER S. W. The quantal nature of transmission and spontaneous miniature potentials at the crayfish neuromuscular junction. J Physiol. 1961 Mar;155:514–529. doi: 10.1113/jphysiol.1961.sp006644. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. DUDEL J. POTENTIAL CHANGES IN THE CRAYFISH MOTOR NERVE TERMINAL DURING REPETITIVE STIMULATION. Pflugers Arch Gesamte Physiol Menschen Tiere. 1965 Jan 11;282:323–337. doi: 10.1007/BF00412507. [DOI] [PubMed] [Google Scholar]
  20. DUDEL J. PRESYNAPTIC INHIBITION OF THE EXCITATORY NERVE TERMINAL IN THE NEUROMUSCULAR JUNCTION OF THE CRAYFISH. Pflugers Arch Gesamte Physiol Menschen Tiere. 1963 Sep 9;277:537–557. [PubMed] [Google Scholar]
  21. Dudel J. The effect of polarizing current on action potential and transmitter release in crayfish motor nerve terminals. Pflugers Arch. 1971;324(3):227–248. doi: 10.1007/BF00586421. [DOI] [PubMed] [Google Scholar]
  22. FALK G., FATT P. LINEAR ELECTRICAL PROPERTIES OF STRIATED MUSCLE FIBRES OBSERVED WITH INTRACELLULAR ELECTRODES. Proc R Soc Lond B Biol Sci. 1964 Apr 14;160:69–123. doi: 10.1098/rspb.1964.0030. [DOI] [PubMed] [Google Scholar]
  23. FATT P., KATZ B. The electrical properties of crustacean muscle fibres. J Physiol. 1953 Apr 28;120(1-2):171–204. doi: 10.1113/jphysiol.1953.sp004884. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Jahromi S. S., Atwood H. L. Correlation of structure, speed of contraction, and total tension in fast and slow abdominal muscle fibers of the lobster (Homarus americanus). J Exp Zool. 1969 May;171(1):25–38. doi: 10.1002/jez.1401710105. [DOI] [PubMed] [Google Scholar]
  25. Jahromi S. S., Atwood H. L. Ultrastructural features of crayfish phasic and tonic muscle fibers. Can J Zool. 1967 Sep;45(5):601–606. doi: 10.1139/z67-076. [DOI] [PubMed] [Google Scholar]
  26. Kennedy D., Evoy W. H. The distribution of pre- and postsynaptic inhibition at crustacean neuromuscular junctions. J Gen Physiol. 1966 Jan;49(3):457–468. doi: 10.1085/jgp.49.3.457. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Kosaka K. Electrophysiological and electron microscopic studies on the neuromuscular junction of the crayfish stretch receptors. Jpn J Physiol. 1969 Apr 15;19(2):160–175. doi: 10.2170/jjphysiol.19.160. [DOI] [PubMed] [Google Scholar]
  28. Kuno M., Turkanis S. A., Weakly J. N. Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog. J Physiol. 1971 Mar;213(3):545–556. doi: 10.1113/jphysiol.1971.sp009399. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Law P. K., Atwood H. L. Membrane resistance change induced by nitrate and other anions in long and short sarcomere muscle fibres of crayfish. Comp Biochem Physiol A Comp Physiol. 1971 Sep 1;40(1):265–271. doi: 10.1016/0300-9629(71)90166-6. [DOI] [PubMed] [Google Scholar]
  30. ORKAND R. K. The relation between membrane potential and contraction in single crayfish muscle fibres. J Physiol. 1962 Apr;161:143–159. doi: 10.1113/jphysiol.1962.sp006878. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Sherman R. G., Atwood H. L. Structure and neuromuscular physiology of a newly discovered muscle in the walking legs of the lobster Homarus americanus. J Exp Zool. 1971 Apr;176(4):461–474. doi: 10.1002/jez.1401760408. [DOI] [PubMed] [Google Scholar]
  32. Stefani E., Steinbach A. B. Resting potential and electrical properties of frog slow muscle fibres. Effect of different external solutions. J Physiol. 1969 Aug;203(2):383–401. doi: 10.1113/jphysiol.1969.sp008869. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Uchizono K. Inhibitory synapses on the stretch receptor neurone of the crayfish. Nature. 1967 May 20;214(5090):833–834. doi: 10.1038/214833a0. [DOI] [PubMed] [Google Scholar]
  34. WEIDMANN S. The electrical constants of Purkinje fibres. J Physiol. 1952 Nov;118(3):348–360. doi: 10.1113/jphysiol.1952.sp004799. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES