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Mejora de la respuesta beta-adrenérgica del miocardio y la señalización con entrenamiento físico en la hipertensión
Scott M MacDonnell1, Hajime Kubo, Deborah L Crabbe
1Department of Kinesiology, Temple University, Philadelphia, PA 19122, USA.
Circulation
|June 22, 2005
Resumen
El entrenamiento físico mejoró la función cardíaca en ratas hipertensas al mejorar la respuesta de los receptores beta-adrenérgicos. Esto se relacionó con la reducción de los niveles de GRK2 y la alteración de las proteínas clave del ciclo del calcio.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Fisiología del ejercicio Fisiología del ejercicio
- Cardiología Molecular Cardiología Molecular
Sus antecedentes:
- Las respuestas cardíacas a la estimulación beta-adrenérgica se ven afectadas en la hipertrofia cardíaca inducida por sobrecarga de presión.
- Investigar el impacto del entrenamiento físico en la respuesta de los receptores beta-adrenérgicos en la hipertensión espontánea es crucial.
Objetivo del estudio:
- Para determinar si el entrenamiento físico modifica la respuesta de los receptores beta-adrenérgicos en la hipertensión espontánea.
- Examinar el papel de los receptores beta-adrenérgicos en la desensibilización de las proteínas ciclistas de la kinasa GRK2 y Ca2+.
Principales métodos:
- Las ratas con hipertensión espontánea (SHR) se sometieron a entrenamiento en cinta de correr (SHR-TRD) o permanecieron sedentarias (SHR-SED). Las ratas Wistar Kyoto (WKY) de la misma edad sirvieron como controles.
- La función del ventrículo izquierdo (LV) se evaluó utilizando preparaciones de Langendorff durante las infusiones de isoproterenol (ISO) y el estrés del ritmo.
- Se analizaron los niveles miocárdicos de GRK2, el canal Ca2+ de tipo L, el intercambiador de sodio y calcio, el receptor de ryanodina y la fosforilación de fosfolambano.
Principales resultados:
- El entrenamiento físico no alteró la presión arterial media, pero aumentó el grosor de la pared LV en SHR.
- SHR-TRD exhibió respuestas inotrópicas y lusitrópicas mejoradas a ISO en comparación con SHR-SED y WKY.
- El entrenamiento normalizó los niveles de GRK2 y aumentó la fosforilación del receptor de ryanodina y el fosfolamban en SHR.
Conclusiones:
- El entrenamiento físico mejora la respuesta beta-adrenérgica en la hipertensión, mejorando la contractilidad cardíaca y la relajación.
- La reducción de la abundancia de GRK2 y el aumento de la fosforilación de las proteínas ciclistas de Ca2+ probablemente median estos efectos beneficiosos.
- El entrenamiento físico ofrece una estrategia potencial para mejorar la función cardíaca en individuos hipertensos.
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