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La disociación neurovascular con la vasodilatación paradójica del antebrazo durante la administración sistémica de
Giris Jacob1, Fernando Costa, Simi Vincent
1Jacob Recanati Autonomic Dysfunction Center, Department of Internal Medicine C, Rambam Medical Center, Haifa, Israel.
Circulation
|April 23, 2003
Resumen
La infusión sistémica de tiramina aumenta la liberación de norepinefrina, pero paradójicamente causa vasodilatación del antebrazo, no vasoconstricción. Esto desafía las suposiciones anteriores sobre los efectos vasculares de la tiramina y la actividad nerviosa simpática.
Área de la Ciencia:
- Farmacología Farmacología.
- Fisiología cardiovascular fisiología cardiovascular.
- La neurociencia es la neurociencia.
Sus antecedentes:
- La tiramina se utiliza para estudiar la liberación de norepinefrina de los nervios simpáticos.
- Sus efectos vasculares, particularmente la vasoconstricción sistémica, son poco conocidos.
- Estudios previos sugieren que la tiramina causa una vasoconstricción sistémica mínima.
Objetivo del estudio:
- Para investigar los efectos vasculares de la infusión sistémica de tiramina.
- Para determinar el impacto de la tiramina en el derrame local de norepinefrina en el antebrazo y la resistencia vascular.
- Para probar la hipótesis de que la tiramina no libera significativamente la norepinefrina de los nervios simpáticos.
Principales métodos:
- Estudió a siete sujetos sanos midiendo el derrame sistémico y local de norepinefrina en el antebrazo y el flujo sanguíneo en el antebrazo.
- Infusión de tiramina sistémica y estimulación simpática inducida a través de la prueba de presión en frío.
- Se midieron los niveles plasmáticos de dopamina en otros seis sujetos durante la administración de tiramina.
Principales resultados:
- La infusión de tiramina aumentó significativamente el derrame de norepinefrina sistémica y en el antebrazo.
- La liberación de norepinefrina en el antebrazo por la tiramina fue comparable a la estimulación por presión fría.
- La tiramina causó vasodilatación del antebrazo, en contraste con la vasoconstricción durante la prueba de presión en frío.
- Los niveles plasmáticos de dopamina aumentaron significativamente con la administración de tiramina.
Conclusiones:
- La infusión sistémica de tiramina aumenta significativamente el derrame de norepinefrina periférica.
- Este aumento en el derrame de norepinefrina está paradójicamente asociado con la vasodilatación local del antebrazo.
- Los efectos vasculares de la tiramina difieren de las expectativas basadas en la liberación de norepinefrina.
Palabras clave:
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