Cultured oligodendrocyte progenitors derived from cerebral cortex express a glycine receptor which is pharmacologically distinct from the neuronal isoform

Authors

  • Shibeshih Belachew,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
    2. Department of Neurology, University of Liège, CHU (B35) Sart Tilman, B-4000 Liège, Belgium
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  • Bernard Rogister,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
    2. Department of Neurology, University of Liège, CHU (B35) Sart Tilman, B-4000 Liège, Belgium
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  • Jean-Michel Rigo,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
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  • Brigitte Malgrange,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
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  • Cécile Mazy-Servais,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
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  • Gaël Xhauflaire,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
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  • Paul Coucke,

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
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  • Gustave Moonen

    1. Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium
    2. Department of Neurology, University of Liège, CHU (B35) Sart Tilman, B-4000 Liège, Belgium
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G. Moonen, Department of Human Physiology and Pathophysiology, University of Liège, 17 Place Delcour, B-4020 Liège, Belgium.

Abstract

Using the whole-cell patch-clamp technique, we demonstrate glycine-induced currents in oligosphere-derived oligodendrocyte progenitors cultured from newborn rats. Similar inward currents are also triggered by β-alanine and taurine, two established glycine receptor agonists. In our recording conditions, glycine-gated currents in oligodendrocyte progenitors reverse about 0 mV and are reversibly inhibited by the glycine competitive antagonist strychnine, the Cl channel blocker picrotoxinin and the non-competitive antagonist cyanotriphenylborate. The oligodendrocyte progenitors glycine receptor (GlyR) differs from the corresponding neuronal receptor: [3H]strychnine binding data and the strychnine inhibition curve of glycine-induced currents in oligodendrocyte progenitor cultures suggest the existence of two strychnine binding sites on the oligodendroglial GlyR. Using total RNA isolated from oligodendrocyte progenitors cultures, reverse transcription–polymerase chain reaction analysis of glycine receptor subunit expression shows the presence of α2 and β subunits and immunocytochemical stainings confirm that this GlyR contains an α subunit which is not α1. The molecular structure of the oligodendroglial GlyR could be either homopentameric α2 or heteromeric α2β but in both cases, the sequence of the α2 or β subunits have to be different from the known neuronal sequences in order to explain, respectively, the cyanotriphenylborate (α2) and picrotoxinin (β) sensitivities. This work thus demonstrates that GlyR are expressed by oligodendrocytes obtained not only from spinal cord but also from supraspinal structures. The pharmacological properties and presumably the molecular structure of oligodendroglial GlyR are original. The physiological meaning of the presence of such receptors on developing and mature oligodendrocytes remains unknown.

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