Abstract
The freeze-fracture appearance of rat stomach and liver gap junctions changes after uncoupling procedures such as inhibition of the metabolism of perfusion with hypertonic sucrose. In control stomach, either fixed immediately or kept for 1 h in a well-oxygenated Tyrode's solution at 37 degrees C, most gap junctions between mucous cells contain particles irregularly packed at an average center-to-center spacing of 10.3-10.5 nm. After 1-h treatment with 2,4-dinitrophenol (DNP), at the same temperature and oxygenation, most particles aggregate hexagonally at an average spacing of approximately 8.5 nm. Similar changes are seen in hypoxic specimens. In control liver, fixed by perfusion, most junctional particles are irregularly packed at an average center-to-center spacing of approximately 10 mm. Small areas of fairly regular hexagonal packing are occasionally seen, where the average particle spacing is 9.2-9.5 nm. In hypoxic liver, the junctional particles form regular hexagonal packings in which the average center-to-center particle spacing is approximately 8.5 nm. In liver perfused with hypertonic sucrose-calcium solutions, following EDTA solutions, most junctions are pulled apart. The separated junctional membranes, expected to be highly impermeable, contain particles regularly and tightly packed as in hypoxic or DNP-treated junctions. Preliminary measurements indicate also a possible change in particle diameter, from approximately 8.6 nm (control) to approximately 7.7 nm (treated). The structural changes are similar to those previously reported in crayfish and may reflect conformational changes in particle subunits resulting in functional uncoupling.
Full Text
The Full Text of this article is available as a PDF (5.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Asada Y., Bennett M. V. Experimental alteration of coupling resistance at an electrotonic synapse. J Cell Biol. 1971 Apr;49(1):159–172. doi: 10.1083/jcb.49.1.159. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BARR L., DEWEY M. M., BERGER W. PROPAGATION OF ACTION POTENTIALS AND THE STRUCTURE OF THE NEXUS IN CARDIAC MUSCLE. J Gen Physiol. 1965 May;48:797–823. doi: 10.1085/jgp.48.5.797. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blaustein M. P., Goldman D. E. The action of certain polyvalent cations on the voltage-clamped lobster axon. J Gen Physiol. 1968 Mar;51(3):279–291. doi: 10.1085/jgp.51.3.279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- De Mello W. C. Effect of intracellular injection of calcium and strontium on cell communication in heart. J Physiol. 1975 Sep;250(2):231–245. doi: 10.1113/jphysiol.1975.sp011051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goodenough D. A., Gilula N. B. The splitting of hepatocyte gap junctions and zonulae occludentes with hypertonic disaccharides. J Cell Biol. 1974 Jun;61(3):575–590. doi: 10.1083/jcb.61.3.575. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., PASSONNEAU J. V., HASSELBERGER F. X., SCHULZ D. W. EFFECT OF ISCHEMIA ON KNOWN SUBSTRATES AND COFACTORS OF THE GLYCOLYTIC PATHWAY IN BRAIN. J Biol Chem. 1964 Jan;239:18–30. [PubMed] [Google Scholar]
- Larsen W. J. Opaque deposits on gap junction membranes after glutaraldehyde-calcium fixation. J Cell Biol. 1975 Dec;67(3):801–813. doi: 10.1083/jcb.67.3.801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loewenstein W. R. Cell surface membranes in close contact. Role of calcium and magnesium ions. J Colloid Interface Sci. 1967 Sep;25(1):34–46. doi: 10.1016/0021-9797(67)90007-0. [DOI] [PubMed] [Google Scholar]
- Martinez-Palomo A., Benitez D., Alanis J. Selective deposition of lanthanum in mammalian cardiac cell membranes. Ultrastructural and electrophysiological evidence. J Cell Biol. 1973 Jul;58(1):1–10. doi: 10.1083/jcb.58.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rose B., Loewenstein W. R. Permeability of cell junction depends on local cytoplasmic calcium activity. Nature. 1975 Mar 20;254(5497):250–252. doi: 10.1038/254250a0. [DOI] [PubMed] [Google Scholar]
- Takata M., Pickard W. F., Lettvin J. Y., Moore J. W. Ionic conductance changes in lobster axon membrane when lanthanum is substituted for calcium. J Gen Physiol. 1966 Nov;50(2):461–471. doi: 10.1085/jgp.50.2.461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thurston J. H., McDougal D. B., Jr Effect of ischemia on metabolism of the brain of the newborn mouse. Am J Physiol. 1969 Feb;216(2):348–352. doi: 10.1152/ajplegacy.1969.216.2.348. [DOI] [PubMed] [Google Scholar]