RESUMEN
Viscum Coloratum Flavonoid (VCF) is one of the dihydro-flavonoids isolated and purified from the stem and leaf of Viscum Coloratum. It was proved both experimentally and clinically to have the effects of anti-tachyarrhythmias. The mechanism of this effect, however, was unclear. In this study, the effects of the drug on the fast response action potentials (FAP) in canine Purkinje fibers and guinea pig ventricular myocardial cells were investigated by glass-microelectrode technique. The results indicated that 0.1 mg/ml VCF accelerated the repolarizations of 2nd and 3rd phase of FAP, shortened action potential duration (APD), and slightly shortened effective refractory period (ERP) (canine) or unchanged (guinea pig). delta ERP/delta APD ratio was increased, therefore, ERP was relatively prolonged. All effects appeared after using the drug for 2 minutes, reached stable status after 10 minutes, and disappeared after washing off the drug for 15 minutes. It was suggested that VCF was the drug which exerted effects rapidly, maintained effects shortly, and had effects reversibly. The cellular electrophysiologic mechanisms of VCF on anti-tachyarrhythmias should be attributed to prolong the ERP relatively and abolish the reentry. This drug is particularly applicable to the tachyarrhythmias due to reentry.
Asunto(s)
Antiarrítmicos/farmacología , Medicamentos Herbarios Chinos/química , Flavonoides/farmacología , Miocardio/citología , Taquicardia/patología , Potenciales de Acción/efectos de los fármacos , Animales , Antiarrítmicos/aislamiento & purificación , Perros , Femenino , Flavonoides/aislamiento & purificación , Cobayas , Técnicas In Vitro , Masculino , Células de Purkinje/efectos de los fármacos , Periodo Refractario Electrofisiológico/efectos de los fármacosRESUMEN
The effects of the total flavonoids of Viscum coloratum (VCF) on the fast response action potentials (FAP) of canine Purkinje fibers and guinea pig ventricular papillary muscles were studied by glass-microelectrode technique. The effects of VCF on the ionic currents through cellular membrane were analysed with selective ion blockers (CsCl, verapamil, and TEA+), respectively. VCF (100 micrograms.ml-1) accelerated the repolarization of FAP and increased delta ERP/delta APD ratio, which were related to decreasing Isi and increasing Ix. It was suggested that the anti-tachyarrhythmic mechanism of VCF was attributed to prolonging ERP relatively and to abolishing reentrant excitation.
Asunto(s)
Antiarrítmicos/farmacología , Medicamentos Herbarios Chinos/farmacología , Flavonoides/farmacología , Ramos Subendocárdicos/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Cesio/farmacología , Cloruros/farmacología , Perros , Femenino , Cobayas , Masculino , Músculos Papilares/efectos de los fármacos , Músculos Papilares/fisiología , Ramos Subendocárdicos/efectos de los fármacos , Periodo Refractario Electrofisiológico/efectos de los fármacos , Compuestos de Tetraetilamonio/farmacología , Verapamilo/farmacologíaRESUMEN
The changes of deformability of RBC and 2,3-DPG in RBC in patients with coronary artery stenosis and the influence of some factors on them were studied. The results showed that: (1) the deformability index was inversely proportional to the degree of lesions of coronary vessels (P less than 0.01); (2) the 2,3-DPG was inversely proportional to the degree of lesions of coronary vessels (P less than 0.01); (3) there was a significant decrease in deformability index after using contrast medium; (4) Saliva may increase deformability of RBC and 2,3-DPG; (5) Nifedipine may increase deformability of RBC. These results showed: (1) the possible existence of microcirculatory dysfunction in coronary artery disease and in parallel of impaired deformability of RBC; (2) the possibility of normalization of the decreased deformability of 2,3-DPG in RBC by Salvia; (3) the possibility of increase of velocity of blood flow in microcirculation in coronary artery disease by Salvia.