Oligodendrocytes express gap junction proteins connexin32 and connexin45

R. Dermietzel*, M. Farooq, J. A. Kessler, H. Althaus, E. L. Hertzberg, D. C. Spray

*Corresponding author for this work

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

Oligodendrocytes, the myelin-forming glia of brain, are connected by gap junctions in situ and in culture. Cultured oligodendrocytes from adult bovine and porcine brains were studied using immunocytochemical, molecular, and electrophysiological techniques in order to characterize the gap junction types. The expression of connexin32 was substantiated by the detection of low, but significant, signals using connexin-specific probes in Northern and Western blot analyses. Connexin43, which comprises gap junctions in astrocytes, was not detectable in pure oligodendrocytic cultures; mRNAs of connexin40 and connexin37 and connexin26 were also not detected. By means of two specific antibodies directed to the recently cloned connexin45 and by RT-PCR we were able to identify this connexin as a second oligodendrocytic gap junction protein. Whole cell voltage clamp recording provided evidence for electrical coupling between pairs of cultured oligodendrocytes (mean junctional conductance 3.9 nS, n = 38 pairs) and intracellular Lucifer Yellow injection indicated that oligodendrocytes were usually only weakly dye coupled, with spread generally being restricted to nearest neighbors. Unitary conductances ranged from >20 to < 150 pS with modes of distribution at about 100 to 120pS and 40 to 20 pS, respectively. These unitary conductances are consistent with the channel events expected for connexin32 and connexin45. The low degree of functional coupling between oligodendrocytes in vitro corresponds with the low levels of connexin32 and connexin45 messenger RNAs and protein expression.

Original languageEnglish (US)
Pages (from-to)101-114
Number of pages14
JournalGlia
Volume20
Issue number2
DOIs
StatePublished - Jun 1 1997

Keywords

  • Connexin32
  • Connexin45
  • Electrical coupling
  • Gap junction
  • Oligodendrocytes

ASJC Scopus subject areas

  • Neurology
  • Cellular and Molecular Neuroscience

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