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El fotoentrenamiento y el reflejo de luz pupillar están mediados por distintas poblaciones de ipRGCs
S-K Chen1, T C Badea, S Hattar
1Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Nature
|July 19, 2011
Resumen
Las células ganglionares retinianas intrínsecamente fotosensibles (ipRGCs) tienen distintos subtipos. Las ipRGCs Brn3b-negativas controlan los ritmos circadianos, mientras que las ipRGCs Brn3b-positivas regulan el reflejo de luz pupillar (PLR).
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Oftalmología Oftalmología.
- Cronobiología cronobiología.
Sus antecedentes:
- Las células ganglionares retinianas intrínsecamente fotosensibles (ipRGCs) expresan melanopsina y son cruciales para las funciones dependientes de la luz.
- Los ipRGCs regulan el fotoentrenamiento circadiano y el reflejo de luz pupillar (PLR).
- Investigaciones anteriores indicaron el papel de los ipRGC, pero carecían de un análisis detallado de la subpoblación.
Objetivo del estudio:
- Para investigar las distintas subpoblaciones de ipRGCs basadas en la expresión del factor de transcripción Brn3b.
- Para diferenciar funcionalmente estas subpoblaciones ipRGC y sus roles específicos en respuestas mediadas por la luz.
Principales métodos:
- Utilizó técnicas de ablación genética para dirigirse selectivamente a las subpoblaciones de ipRGC.
- Examinó los patrones de inervación de los ipRGCs Brn3b-negativo y Brn3b-positivo en el cerebro.
- Evaluó el impacto de la ablación selectiva en el fotoentrenamiento circadiano y el PLR.
Principales resultados:
- Se identificaron dos subpoblaciones distintas de ipRGC: las ipRGCs Brn3b-negativas M1 y las ipRGCs Brn3b-positivas.
- Brn3b-negativo M1 ipRGCs innervan el núcleo supraquiasmático (SCN), crucial para los ritmos circadianos.
- Las ipRGCs Brn3b positivas innervan el núcleo pretectal olivar y otras regiones cerebrales, mediando la PLR.
- La ablación selectiva de los ipRGC positivos para Brn3b abolió la PLR pero preservó el fotoentrenamiento circadiano.
Conclusiones:
- Las ipRGCs comprenden subpoblaciones funcionalmente distintas definidas por la expresión Brn3b.
- Las ipRGCs M1 negativas de Brn3b son esenciales para el fotoentrenamiento circadiano.
- Los ipRGCs positivos para Brn3b son críticos para regular el reflejo de luz pupillar (PLR).
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