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Measuring Fast Calcium Fluxes in Cardiomyocytes
Published on: November 29, 2011
La liberación pulsante de calcio intracelular no depende de las fluctuaciones en la concentración de inositol
M Wakui1, B V Potter, O H Petersen
1MRC Secretory Control Research Group, University of Liverpool, UK.
Nature
|May 25, 1989
Resumen
Las hormonas desencadenan las oscilaciones del calcio celular a través del trisfosfato de inositol (InsP3). Este estudio demuestra que la liberación de calcio puede ser regular incluso con niveles constantes de InsP3, desafiando los modelos existentes.
Área de la Ciencia:
- Fisiología celular La fisiología celular.
- La bioquímica es la bioquímica.
- Las vías de señalización.
Sus antecedentes:
- La señalización celular implica oscilaciones en la concentración de calcio intracelular ([Ca2+]i).
- El trisfosfato de inositol (InsP3) es un mensajero clave que estimula la liberación de calcio de las reservas intracelulares.
- Los modelos actuales a menudo asumen que los niveles fluctuantes de InsP3 impulsan oscilaciones [Ca2+]i.
Objetivo del estudio:
- Para investigar el mecanismo que genera regulares oscilaciones intracelulares de calcio en las células no excitables.
- Para determinar si los niveles constantes de inositol trisfosfato (InsP3) pueden producir pulsos regulares de liberación de calcio.
- Desafiar el modelo prevaleciente de que la fluctuación de InsP3 es esencial para las oscilaciones [Ca2+]i.
Principales métodos:
- Monitoreo de la concentración de calcio intracelular ([Ca2+]i) a través de corrientes de Cl- activadas por Ca2+ en células acinares pancreáticas de un solo ratón.
- Estimulando las células con acetilcolina (ACh) y aplicando inositol trisfosfato (InsP3) y su análogo (InsPS3) a través de una pipeta de parche.
- Realizar experimentos con y sin calcio externo, y con quelantes de calcio intracelulares.
Principales resultados:
- La acetilcolina (ACh) y el InsP3 evocaron pulsos regulares y repetitivos de corriente Cl- activada por Ca2+, lo que indica una liberación regular de calcio.
- El análogo no metabolizable de InsP3, InsPS3, también produjo pulsos regulares de liberación de calcio.
- Estos eventos de liberación de calcio fueron independientes del calcio externo pero sensibles a la quelación intracelular del calcio.
Conclusiones:
- La liberación repetitiva de calcio intracelular puede ocurrir incluso cuando la concentración de trifosfato de inositol (InsP3) permanece constante.
- Este hallazgo sugiere que otros mecanismos además de los fluctuantes niveles de InsP3 contribuyen a las oscilaciones regulares del calcio.
- El estudio proporciona evidencia en contra de la necesidad de una InsP3 fluctuante para generar oscilaciones regulares [Ca2+]i.
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