Two pools of Triton X-100-insoluble GABA(A) receptors are present in the brain, one associated to lipid rafts and another one to the post-synaptic GABAergic complex.
J Neurochem
; 102(4): 1329-45, 2007 Aug.
Article
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| MEDLINE
| ID: mdl-17663755
Rat forebrain synaptosomes were extracted with Triton X-100 at 4 degrees C and the insoluble material, which is enriched in post-synaptic densities (PSDs), was subjected to sedimentation on a continuous sucrose gradient. Two pools of Triton X-100-insoluble gamma-aminobutyric acid type-A receptors (GABA(A)Rs) were identified: (i) a higher-density pool (rho = 1.10-1.15 mg/mL) of GABA(A)Rs that contains the gamma2 subunit (plus alpha and beta subunits) and that is associated to gephyrin and the GABAergic post-synaptic complex and (ii) a lower-density pool (rho = 1.06-1.09 mg/mL) of GABA(A)Rs associated to detergent-resistant membranes (DRMs) that contain alpha and beta subunits but not the gamma2 subunit. Some of these GABA(A)Rs contain the delta subunit. Two pools of GABA(A)Rs insoluble in Triton X-100 at 4 degrees C were also identified in cultured hippocampal neurons: (i) a GABA(A)R pool that forms clusters that co-localize with gephyrin and remains Triton X-100-insoluble after cholesterol depletion and (ii) a GABA(A)R pool that is diffusely distributed at the neuronal surface that can be induced to form GABA(A)R clusters by capping with an anti-alpha1 GABA(A)R subunit antibody and that becomes solubilized in Triton X-100 at 4 degrees C after cholesterol depletion. Thus, there is a pool of GABA(A)Rs associated to lipid rafts that is non-synaptic and that has a subunit composition different from that of the synaptic GABA(A)Rs. Some of the lipid raft-associated GABA(A)Rs might be involved in tonic inhibition.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sinaptosomas
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Encéfalo
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Receptores de GABA-A
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Microdominios de Membrana
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Ácido gamma-Aminobutírico
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
J Neurochem
Año:
2007
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Reino Unido