Cultured Oligodendrocyte Progenitors Derived from Cerebral Cortex Express a Glycine Receptor Which Is Pharmacologically Distinct from the Neuronal Isoform
[en] 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 beta-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 alpha2 and beta subunits and immunocytochemical stainings confirm that this GlyR contains an alpha subunit which is not alpha1. The molecular structure of the oligodendroglial GlyR could be either homopentameric alpha2 or heteromeric alpha2beta but in both cases, the sequence of the alpha2 or beta subunits have to be different from the known neuronal sequences in order to explain, respectively, the cyanotriphenylborate (alpha2) and picrotoxinin (beta) 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.
Belachew, Shibeshih ; Université de Liège - ULiège > Département des sciences cliniques > Neurologie
Rogister, Bernard ; Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biochimie et physiologie générales, et biochimie humaine
Rigo, Jean-Michel
Malgrange, Brigitte ; Université de Liège - ULiège > CNCM/ Centre fac. de rech. en neurobiologie cell. et moléc.
Mazy-Servais, Cécile
Xhauflaire, Gaël ; Centre Hospitalier Universitaire de Liège - CHU > Ophtalmologie
Coucke, Paul
Moonen, Gustave ; Université de Liège - ULiège > Département des sciences cliniques > Neurologie - Doyen de la Faculté de Médecine
Language :
English
Title :
Cultured Oligodendrocyte Progenitors Derived from Cerebral Cortex Express a Glycine Receptor Which Is Pharmacologically Distinct from the Neuronal Isoform
Avellana-Adalid, V., Nait Oumesmar, B., Lachapelle, F. & Baron-Van Evercooren, A. (1996) Expansion of rat oligodendrocyte progenitors into proliferative 'oligospheres' that retain differentiation potential. J. Neurosci. Res., 45, 558-570.