Abstract:ObjectiveTo observe the effect of Polygonum Bistorla's n-Butyl alcohol extract (PBNA)on excitability and functional refractory period (FRP) of excised guinea pig pulmonary atrium and to discuss its mechanism. MethodsThe effect of PBNA on excised guinea pig pulmonary atrium was investigated by intensity-time curve and FRP. ResultsPBNA upper-shifted intensity-time curve and shortened FRP on excised pulmonary atrium which was in proportion with the extract's dosage. ConclusionPBNA has an effect of reducing excitability and shortening FRP of excised pulmonary atrium in a manner of dosagedependent. It may work through inhibiting membrane voltagedependent Na+ channel and promoting an outflow K+ with cardiac muscle cells.
[20] Li HT, Wang YQ, Dai DZ, et al. Frequency dependent prolongation of effective refractory period by a complex class III antiarrhythmic agent CPU-86017[J].Acta Pharmacol Sin,2001,22(1):32.