Functional excitatory GABAA receptors precede ionotropic glutamate receptors in radial glia-like neural stem cells.
The involvement of neurotransmission in neuronal development is a generally accepted concept. Nevertheless, the precise regulation of neurotransmitter receptor expression is still unclear. To investigate the expression profiles of the most important ionotropic neurotransmitter receptors, namely GABA(A) receptors (GABA(A)Rs), NMDA receptors (NMDARs), and AMPA receptors (AMPARs), quantitative RT-PCR, immunoblot analysis and patch clamp studies were performed in in vitro-generated neural stem cells (NSCs). This clearly defined cell line is closely related to radial glia cells, the stem cells in the neonate brain. We found functional GABA(A)Rs of the subunit composition alpha2, beta3, and gamma1 to be expressed. Unexpectedly, functional ionotropic glutamate receptors were absent. However, NSCs expressed the NMDAR subunits NR2A and NR3A, and the AMPAR subunit GluR4 at the protein level, and GluR3 at the mRNA level. The overexpression of functional NMDARs in NSCs led to an increased mRNA level of AMPAR subunits, indicating a role in synaptogenesis. Early neuronal markers remained unchanged. These data extend our knowledge about ionotropic neurotransmitter receptor expression during neuronal development and will aid further investigations on activity-dependent neurogenesis.
Muth-Köhne
Elke
E
Department of Biochemistry I-Receptor Biochemistry, Ruhr University Bochum, D-44780 Bochum, Germany.
Terhag
Jan
J
Pahl
Steffen
S
Werner
Markus
M
Joshi
Illah
I
Hollmann
Michael
M
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000502:physiology*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D051379:Mice; D016202:N-Methylaspartate / Q000494:pharmacology; D055495:Neurogenesis / Q000502:physiology; D009457:Neuroglia / Q000378:metabolism* / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques / Q000379:methods; D026902:Potassium Channel Blockers / Q000494:pharmacology; D021122:Protein Subunits / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D055748:SOXB1 Transcription Factors / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters / Q000235:genetics / Q000378:metabolism; D064506:Solute Carrier Family 12, Member 2; D019789:Tetraethylammonium / Q000494:pharmacology; D014162:Transfection / Q000379:methods; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018756:GABA Antagonists; C409466:NR1 NMDA receptor; C121001:NR2B NMDA receptor; D026902:Potassium Channel Blockers; D021122:Protein Subunits; D012333:RNA, Messenger; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D055748:SOXB1 Transcription Factors; C578878:Slc12a2 protein, mouse; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; C098693:Sox1 protein, mouse; C485184:enhanced green fluorescent protein; D016222:Fibroblast Growth Factor 2; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid; D004815:Epidermal Growth Factor; D016202:N-Methylaspartate; D019789:Tetraethylammonium; D001640:Bicuculline