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. 1977 Jan 1;72(1):26–34. doi: 10.1083/jcb.72.1.26

Freeze-fracture studies of nexuses between smooth muscle cells. Close relationship to sarcoplasmic reticulum

PMCID: PMC2110984  PMID: 401506

Abstract

The freeze-fracture appearance of the nexus was compared in the smooth muscle of guinea pig sphincter pupillac, portal vein, pulmonary artery, taenia coli, uretzr, and vas diferens, mouse vas deferens, chicken gizzard and anterior mesenteric artery, and toad stomach. Nexuses are particularly numerous in the guinea pig sphincter pupillae; they are usually oval and their average area is 0.15 mum2, although some as large as 0.6 mum2 were seen. Small aggregations of particles were observed which would not be recognizable as nexuses in thin section. What constitutes the minimum size of a nexus is discussed. It is estimated that the number of nexuses per cell in this preparation is of the order of tens rather than hundreds. All nexuses examined had 6-9-nm particles in the PF face, with corresponding 3-4-nm pits on the EF face forming a polygonal tending towards a hexagonal lattice. The nexuses are arranged in rows parallel to the main axis of the cell, usually alternating with longitudinal rows of plasmalemmal vesicles. Many nexuses in the guinea pig sphincter pupillae, chicken gizzard, and toad stomach show a close relationship with sarcoplasmic reticulum. The possibility that this may have some role in current flow across this specialized junction is discussed.

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Selected References

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

  1. Albertini D. F., Anderson E. Structural modifications of lutein cell gap junctions during pregnancy in the rat and the mouse. Anat Rec. 1975 Feb;181(2):171–194. doi: 10.1002/ar.1091810203. [DOI] [PubMed] [Google Scholar]
  2. BERGMAN R. A. Intercellular bridges in ureteral smooth muscle. Bull Johns Hopkins Hosp. 1958 Apr;102(4):195–202. [PubMed] [Google Scholar]
  3. Barr L., Berger W., Dewey M. M. Electrical transmission at the nexus between smooth muscle cells. J Gen Physiol. 1968 Mar;51(3):347–368. doi: 10.1085/jgp.51.3.347. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bennett M. V. Function of electrotonic junctions in embryonic and adult tissues. Fed Proc. 1973 Jan;32(1):65–75. [PubMed] [Google Scholar]
  5. Branton D., Bullivant S., Gilula N. B., Karnovsky M. J., Moor H., Mühlethaler K., Northcote D. H., Packer L., Satir B., Satir P. Freeze-etching nomenclature. Science. 1975 Oct 3;190(4209):54–56. doi: 10.1126/science.1166299. [DOI] [PubMed] [Google Scholar]
  6. Branton D. Freeze-etching studies of membrane structure. Philos Trans R Soc Lond B Biol Sci. 1971 May 27;261(837):133–138. doi: 10.1098/rstb.1971.0043. [DOI] [PubMed] [Google Scholar]
  7. Campbell G. R., Uehara Y., Mark G., Burnstock G. Fine structure of smooth muscle cells grown in tissue culture. J Cell Biol. 1971 Apr;49(1):21–34. doi: 10.1083/jcb.49.1.21. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Chalcroft J. P., Bullivant S. An interpretation of liver cell membrane and junction structure based on observation of freeze-fracture replicas of both sides of the fracture. J Cell Biol. 1970 Oct;47(1):49–60. doi: 10.1083/jcb.47.1.49. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Cobb J. L., Bennett T. A study of nexuses in visceral smooth muscle. J Cell Biol. 1969 Apr;41(1):287–297. doi: 10.1083/jcb.41.1.287. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Devine C. E., Somlyo A. V., Somlyo A. P. Sarcoplasmic reticulum and excitation-contraction coupling in mammalian smooth muscles. J Cell Biol. 1972 Mar;52(3):690–718. doi: 10.1083/jcb.52.3.690. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Dewey M. M., Barr L. Intercellular Connection between Smooth Muscle Cells: the Nexus. Science. 1962 Aug 31;137(3531):670–672. doi: 10.1126/science.137.3531.670-a. [DOI] [PubMed] [Google Scholar]
  12. Friend D. S., Gilula N. B. Variations in tight and gap junctions in mammalian tissues. J Cell Biol. 1972 Jun;53(3):758–776. doi: 10.1083/jcb.53.3.758. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Gabella G. Intercellular junctions between circular and longitudinal intestinal muscle layers. Z Zellforsch Mikrosk Anat. 1972;125(2):191–199. doi: 10.1007/BF00306788. [DOI] [PubMed] [Google Scholar]
  14. Gabella G. The sphincter pupillae of the guinea-pig: structure of muscle cells, intercellular relations and density of innervation. Proc R Soc Lond B Biol Sci. 1974 Jul 30;186(1085):369–386. doi: 10.1098/rspb.1974.0055. [DOI] [PubMed] [Google Scholar]
  15. Johnson R. G., Sheridan J. D. Junctions between cancer cells in culture: ultrastructure and permeability. Science. 1971 Nov 12;174(4010):717–719. doi: 10.1126/science.174.4010.717. [DOI] [PubMed] [Google Scholar]
  16. McNutt N. S., Weinstein R. S. Membrane ultrastructure at mammalian intercellular junctions. Prog Biophys Mol Biol. 1973;26:45–101. doi: 10.1016/0079-6107(73)90017-5. [DOI] [PubMed] [Google Scholar]
  17. PROSSER C. L., BURNSTOCK G., KAHN J. Conduction in smooth muscle: comparative structural properties. Am J Physiol. 1960 Sep;199:545–552. doi: 10.1152/ajplegacy.1960.199.3.545. [DOI] [PubMed] [Google Scholar]
  18. Popescu L. M., Diculescu I., Zelck U., Ionescu N. Ultrastructural distribution of calcium in smooth muscle cells of guinea-pig taenia coli. A correlated electron microscopic and quantitative study. Cell Tissue Res. 1974;154(3):357–378. doi: 10.1007/BF00223732. [DOI] [PubMed] [Google Scholar]
  19. Raviola E., Gilula N. B. Gap junctions between photoreceptor cells in the vertebrate retina. Proc Natl Acad Sci U S A. 1973 Jun;70(6):1677–1681. doi: 10.1073/pnas.70.6.1677. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Rayns D. G., Devine C. E., Sutherland C. L. Freeze fracture studies of membrane systems in vertebrate muscle. I. Striated muscle. J Ultrastruct Res. 1975 Mar;50(3):306–321. doi: 10.1016/s0022-5320(75)80063-3. [DOI] [PubMed] [Google Scholar]
  21. Somlyo A. P., Devine C. E., Somlyo A. V. Thick filaments in unstretched mammalian smooth muscle. Nature. 1971 Oct 13;233(5320):218–219. [PubMed] [Google Scholar]
  22. Somlyo A. P., Somlyo A. V., Devine C. E., Peters P. D., Hall T. A. Electron microscopy and electron probe analysis of mitochondrial cation accumulation in smooth muscle. J Cell Biol. 1974 Jun;61(3):723–742. doi: 10.1083/jcb.61.3.723. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Uehara Y., Burnstock G. Demonstration of "gap junctions" between smooth muscle cells. J Cell Biol. 1970 Jan;44(1):215–217. doi: 10.1083/jcb.44.1.215. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Uehara Y., Burnstock G. Postsynaptic specialization of smooth muscle at close neuromuscular junctions in the guinea pig sphincter pupillae. J Cell Biol. 1972 Jun;53(3):849–853. doi: 10.1083/jcb.53.3.849. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Watanabe H., Yamamoto T. Y. Freeze-etch study of smooth muscle cells from vas deferens and taenia coli. J Anat. 1974 Jul;117(Pt 3):553–564. [PMC free article] [PubMed] [Google Scholar]

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