γ-Aminobutyric acid-ρ expression in ependymal glial cells of the mouse cerebellum.
The ependymal glial cells (EGCs) from the periventricular zone of the cerebellum were studied to determine their distribution and the functional properties of their γ-aminobutyric acid type A (GABA(A) ) receptors. EGCs were identified by the presence of ciliated structures on their ventricular surface and their expression of glial fibrillary acidic protein (GFAP). Interestingly, diverse cell types, including neurons, astrocytes, and other types of glia, were identified in the subventricular zone by their current profiles. Electron microscopy showed ciliated cells and myelinated axons in this zone, but we found no collateral connections to suggest the presence of functional synapses. GABA-mediated currents were recorded from EGCs in cerebellar slices from postnatal days 13 to 35 (PN13-PN35). These currents were blocked by TPMPA (a highly specific GABA(A) ρ subunit antagonist) and bicuculline (a selective antagonist for classic GABA(A) receptors). Pentobarbital failed to modulate GABA(A)-mediated currents despite the expression of GABAα1 and GABAγ2 subunits. In situ hybridization, RT-PCR, and immunofluorescence studies confirmed GABAρ1 expression in EGCs of the cerebellum. We conclude that cerebellar EGCs express GABAρ1, which is functionally involved in GABA(A) receptor-mediated responses that are unique among glial cells of the brain.
Departamento de Neurobiología Molecular y Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Juriquilla, Querétaro, México.
Daniel
D
Reyes-Haro
María Alejandra
MA
González-González
Adriana
A
Pétriz
Abraham
A
Rosas-Arellano
Helmut
H
Kettenmann
Ricardo
R
Miledi
Ataulfo
A
Martínez-Torres
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004805:Ependyma / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D058787:GABA-A Receptor Antagonists; D021122:Protein Subunits; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline