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Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells
Published on: October 1, 2010
La permeabilidad de Ca2+ de los canales de receptores de glutamato por KA-AMPA depende de la composición de las
M Hollmann1, M Hartley, S Heinemann
1Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037.
Science (New York, N.Y.)
|May 10, 1991
Resumen
Los receptores no NMDA, que normalmente pasan iones monovalentes, pueden conducir el calcio cuando están presentes subunidades específicas (GluR1, GluR3). Este hallazgo sugiere que el glutamato puede activar eventos dependientes del calcio a través de estos receptores no NMDA.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los receptores de glutamato vinculados a los canales iónicos son cruciales para la señalización neuronal.
- Los receptores NMDA y los receptores no NMDA son las dos clases principales.
- Tradicionalmente se creía que los receptores no NMDA sólo conducían cationes monovalentes.
Objetivo del estudio:
- Para investigar la permeabilidad de los canales de los receptores no NMDA a los cationes divalentes.
- Para determinar si las subunidades específicas de los receptores de glutamato influyen en la permeabilidad iónica.
- Explorar el potencial de los receptores no NMDA para mediar la afluencia de calcio.
Principales métodos:
- Expresión de las subunidades del receptor de glutamato (GluR1, GluR2, GluR3) en los óvulos de Xenopus.
- Aplicación de ácido kaínico (KA) y ácido propiónico alfa-amino-3-hidroxi-5-metil-4-isoxazol (AMPA) en canales cerrados.
- Medición de las corrientes iónicas, específicamente las corrientes de calcio, en potenciales fisiológicos de reposo.
Principales resultados:
- Los ovocitos que expresan GluR1, GluR3 o GluR1+GluR3 exhibieron corrientes de calcio hacia adentro tras la estimulación de KA y AMPA.
- Los ovocitos que expresan GluR1+GluR2 o GluR3+GluR2 no mostraron permeabilidad al calcio.
- La presencia de la subunidad GluR2 parecía prevenir la conductividad de los iones de calcio.
Conclusiones:
- Ciertas combinaciones de subunidades de receptores no NMDA (específicamente las que carecen de GluR2) pueden conducir iones de calcio.
- La activación del glutamato de los receptores no NMDA puede conducir a una afluencia de calcio en las neuronas que expresan estas subunidades específicas.
- Esta afluencia de calcio a través de receptores no NMDA puede desencadenar eventos intracelulares dependientes del calcio.
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