Direct recording of EDP-EDV relationship in isolated rat left ventricle: effect of diastolic crossbridge formation.
Cardiovasc Res
; 28(5): 715-9, 1994 May.
Article
en En
| MEDLINE
| ID: mdl-8025918
ABSTRACT
OBJECTIVE:
The aim was to investigate whether the end diastolic pressure-end diastolic volume (EDP-EDV) relationship of the left ventricle can be influenced by calcium dependent elements, especially at low values of end diastolic pressure.METHODS:
Isolated rat hearts were perfused in a modified Langendorff perfusion system. The EDP-EDV relationship of the left ventricle was investigated. Pressure was recorded with a microtip pressure catheter and volume with a microconductance catheter. Crossbridge cycling was affected by adding calcium antagonists (verapamil, diltiazem, nifedipine at 2.10(-7) M) or by adding the Mg-ATPase blocker BDM (2,3-butanedione-2-monoxime, 10(-3) M) to the perfusate.RESULTS:
The above had a negative inotropic effect in systole. At EDP = 0 after stimulation the active isovolumetric pressure was zero. In diastole, BDM shifted the EDP-EDV relationship to slightly smaller EDVs. A decrease of about 5% in the EDV was found at lower EDP values. Ca2+ antagonists increased the EDV up to 40-80% at low EDP values. At higher EDP values only a small increase of EDV (about 10%) was found after verapamil perfusion. The results obtained are interpreted in terms of a three step crossbridge model.CONCLUSIONS:
At low EDP, diastolic volume is dependent upon weakly bound crossbridges as a function of the [Ca2+] in the cardiac cell.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Volumen Sistólico
/
Presión Sanguínea
/
Bloqueadores de los Canales de Calcio
/
Función Ventricular Izquierda
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Cardiovasc Res
Año:
1994
Tipo del documento:
Article
País de afiliación:
Países Bajos