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La serotonina agrava selectivamente la isquemia subendocárdica distal a una estenosis de la arteria coronaria durante
R J Bache1, R P Stark, D J Duncker
1Cardiovascular Division, University of Minnesota Medical School, Minneapolis 55455.
Circulation
|November 1, 1992
Resumen
La serotonina dilata los vasos coronarios normalmente, pero contrae el flujo subendocárdico durante la hipoperfusión inducida por el ejercicio. Esto sugiere que la serotonina aumenta selectivamente la resistencia al flujo sanguíneo en el subendocardio.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Farmacología Farmacología.
Sus antecedentes:
- La circulación coronaria sigue respondiendo a los estímulos durante la isquemia miocárdica.
- La serotonina tiene propiedades vasodilatadoras y vasoconstrictoras.
- Se investigaron sus efectos sobre la circulación coronaria durante la hipoperfusión.
Objetivo del estudio:
- Para examinar el efecto de la serotonina en la circulación coronaria distal a una estenosis que causa hipoperfusión miocárdica durante el ejercicio.
- Para determinar si las propiedades duales de la serotonina influyen en la distribución del flujo sanguíneo en condiciones isquémicas.
Principales métodos:
- Se estudiaron siete perros con instrumentos crónicos durante el ejercicio de la cinta de correr con una estenosis de la arteria coronaria.
- El flujo sanguíneo del miocardio se midió utilizando microsferas radiactivas antes y durante la infusión de serotonina.
- La estenosis se ajustó para mantener constante la presión coronaria distal.
Principales resultados:
- Durante el ejercicio con estenosis, el flujo sanguíneo del miocardio disminuyó en un 45%, más significativamente en el subendocardio.
- La infusión de serotonina (0,4-2,0 μg/kg/min) disminuyó el flujo subendocárdico y tendía a aumentar el flujo subepicárdico sin alterar la presión distal.
- En el flujo arterial normal, la serotonina aumentó el flujo sanguíneo subendocárdico y subepicárdico.
Conclusiones:
- La serotonina dilata los vasos de resistencia coronaria y aumenta el flujo a todas las capas miocárdicas en condiciones normales.
- Durante la hipoperfusión, la serotonina causó vasodilatación en el subepicardio pero vasoconstricción en el subendocardio.
- La serotonina parece estrechar las arterias penetrantes intramurales, aumentando selectivamente la resistencia al flujo sanguíneo subendocárdico.
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