Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1973 Mar;70(3):822–826. doi: 10.1073/pnas.70.3.822

Synaptic Differentiation in a Regenerating Crab-Limb Muscle

C K Govind 1, H L Atwood 1, Fred Lang 1,*
PMCID: PMC433367  PMID: 4514993

Abstract

Properties of synapses on regenerating nerve terminals of the single excitatory axon to the stretcher muscle were studied in the regenerating second walking leg of the shore crab, Grapsus. In the adult condition these synapses vary in physiological properties, ranging from high release, poorly facilitating types to low release, highly facilitating types. Synapses on regenerating stretcher-muscle fibers show a distinct temporal pattern of differentiation. In early limb buds, a characteristic fluctuating, excitatory postsynaptic potential, punctuated by failures of transmission, is seen, indicating a developmentally “naive” synapse with low quantal content. In these early stages proportionately more synapses are of the poorly facilitating type; the highly facilitating synapses appear increasingly in later stages. Thus, the type of synapse that will form seems likely to be related to the time of innervation. Synapses of early developmental stages found by electron microscopy are significantly smaller than those seen in adult muscles; thus, the synaptic contact area must increase during development. We postulate that contacts formed by the primary branches of the axon early in development differentiate into relatively large, poorly facilitating synapses, while contacts formed by secondary branches slightly later in development differentiate into smaller, highly facilitating synapses.

Keywords: synaptic diversity, limb regeneration, synaptogenesis differentiation, crustacean muscle

Full text

PDF
822

Images in this article

824Image
on p.824
824Image
on p.824
824Image
on p.824

Selected References

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

  1. 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]
  2. 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]
  3. 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]
  4. Fischbach G. D. Synapse formation between dissociated nerve and muscle cells in low density cell cultures. Dev Biol. 1972 Jun;28(2):407–429. doi: 10.1016/0012-1606(72)90023-1. [DOI] [PubMed] [Google Scholar]
  5. Fischbach G. D. Synaptic potentials recorded in cell cultures of nerve and muscle. Science. 1970 Sep 25;169(3952):1331–1333. doi: 10.1126/science.169.3952.1331. [DOI] [PubMed] [Google Scholar]
  6. James D. W., Tresman R. L. De novo formation of neuro-muscular junctions in tissue culture. Nature. 1968 Oct 26;220(5165):384–385. doi: 10.1038/220384a0. [DOI] [PubMed] [Google Scholar]
  7. Kim S. U., Wenger E. L. De novo formation of synapses in cultures of chick neural tube. Nat New Biol. 1972 Apr 5;236(66):152–153. doi: 10.1038/newbio236152a0. [DOI] [PubMed] [Google Scholar]
  8. Oppenheim R. W., Foelix R. F. Synaptogenesis in the chick embryo spinal cord. Nat New Biol. 1972 Jan 26;235(56):126–128. doi: 10.1038/newbio235126a0. [DOI] [PubMed] [Google Scholar]
  9. Robbins N., Yonezawa T. Developing neuromuscular junctions: first signs of chemical transmission during formation in tissue culture. Science. 1971 Apr 23;172(3981):395–398. doi: 10.1126/science.172.3981.395. [DOI] [PubMed] [Google Scholar]
  10. Robbins N., Yonezawa T. Physiological studies during formation and development of rat neuromuscular junctions in tissue culture. J Gen Physiol. 1971 Oct;58(4):467–481. doi: 10.1085/jgp.58.4.467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Seecof R. L., Teplitz R. L., Gerson I., Ikeda K., Donady J. Differentiation of neuromuscular junctions in cultures of embryonic Drosophila cells. Proc Natl Acad Sci U S A. 1972 Mar;69(3):566–570. doi: 10.1073/pnas.69.3.566. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Sherman R. G., Atwood H. L. Correlated electrophysiological and ultrastructural studies of a crustacean motor unit. J Gen Physiol. 1972 May;59(5):586–615. doi: 10.1085/jgp.59.5.586. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. 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]
  14. Sherman R. G., Atwood H. L. Synaptic facilitation: long-term neuromuscular facilitation in crustaceans. Science. 1971 Mar 26;171(3977):1248–1250. doi: 10.1126/science.171.3977.1248. [DOI] [PubMed] [Google Scholar]
  15. Shimada Y., Fischman D. A., Moscona A. A. Formation of neuromuscular junctions in embryonic cell cultures. Proc Natl Acad Sci U S A. 1969 Mar;62(3):715–721. doi: 10.1073/pnas.62.3.715. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. TAKEUCHI A., TAKEUCHI N. LOCALIZED ACTION OF GAMMA-AMINOBUTYRIC ACID ON THE CRAYFISH MUSCLE. J Physiol. 1965 Mar;177:225–238. doi: 10.1113/jphysiol.1965.sp007588. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES