Differential expression of α1 and β subunits of voltage dependent Ca2+ channel at the neuromuscular junction of normal and P/Q Ca2+ channel knockout mouse
Voltage-dependent calcium channels (VDCC) have a key role in neuronal function transforming the voltage signals into intracellular calcium signals. They are composed of the pore-forming α1 and the regulatory α2δ, γ and β subunits. Molecular and functional studies have revealed which α1 subunit gene...
Guardado en:
| Autores principales: | , |
|---|---|
| Publicado: |
2004
|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03064522_v123_n1_p75_Pagani http://hdl.handle.net/20.500.12110/paper_03064522_v123_n1_p75_Pagani |
| Aporte de: |
| Sumario: | Voltage-dependent calcium channels (VDCC) have a key role in neuronal function transforming the voltage signals into intracellular calcium signals. They are composed of the pore-forming α1 and the regulatory α2δ, γ and β subunits. Molecular and functional studies have revealed which α1 subunit gene product is the molecular constituent of each class of native calcium channel (L, N, P/Q, R and T type). Electrophysiological and immunocytochemical studies have suggested that at adult mouse motor nerve terminal (MNT) only P/Q type channels, formed by α1A subunit, mediate evoked transmitter release. The generation of α1A-null mutant mice offers an opportunity to study the expression and localization of calcium channels at a synapse with complete loss of P/Q calcium channel. We have investigated the expression and localization of VDCCs α1 and β subunits at the wild type (WT) and knockout (KO) mouse neuromuscular junction (NMJ) using fluorescence immunocytochemistry. The α1A subunit was observed only at WT NMJ and was absent at denervated muscles and at KO NMJ. The subunits α1B, α1D and α1E were also present at WT NMJ and they were over- expressed at KO NMJ suggesting a compensatory expression due to the lack of the α1A. On the other hand, the β1b, β2a and β4 were present at the same levels in both genotypes. The presence of other types of VDCC at WT NMJ indicate that they may play other roles in the signaling process which have not been elucidated and also shows that other types of VDCC are able to substitute the α1A subunit, P/Q channel under certain pathological conditions. © 2003 IBRO. Published by Elsevier Ltd. All rights reserved. |
|---|