ABSTRACT
AIM:To study the electrophysiological effects of amiodarone on the pacemaker cells in guinea-pig left ventricular outflow tract under the conditions of hypoxia,acidosis and treatment with epinephrine.METHODS:The action potentials of the pacemaker cells in guinea-pig left ventricular outflow tract were recorded by conventional intracellular microelectrode technique.The effects of amiodarone on the spontaneous slow response potentials were investigated under the conditions of hypoxia,acidosis and treatment with epinephrine.RESULTS:(1) Amiodarone at concentration of 0.1 ?mol/L markedly decreased the rate of pacemaker firing (RPF) and maximal diastolic potential (MDP),lengthened 80% of the duration of action potential (APD80).Amiodarone at concentration of 1 ?mol/L significantly decreased the velocity of diastolic depolarization (VDD) and RPF,the maximal rate of depolarization (Vmax),MDP and amplitude of action potential (APA),lengthened 50% of the duration of action potential (APD50) and APD80.Amiodarone at concentration of 10 ?mol/L led to a significant decrease in VDD and RPF,Vmax,MDP and APA,a notable lengthening in APD50 and APD80 was also observed.(2) Under the condition of hypoxia and perfusion with deprived glucose content for 15 min,VDD,RPF,MDP,Vmax and APA decreased significantly,APD50 was shortened notably.Under the condition of hypoxia,amiodarone at concentration of 1 ?mol/L significantly decreased VDD,RPF and Vmax,increased MDP,lengthened APD50 and APD80 as compared to the cells treated with hypoxia only.(3) Perfusion with pH 6.8 solution for 10 min,VDD and RPF significantly decreased,Vmax and APA notably reduced,APD80 was markedly shortened.Under the condition of acidosis for 10 min,amiodarone significantly decreased VDD,RPF,MDP and APA,lengthened APD50 and APD80 as compared to the cells under the condition of acidosis only.(4) Perfusion of epinephrine at concentration of 10 ?mol/L for 10 min resulted in a significant increase in VDD,RPF,Vmax,MDP and APA,a notable shorting in APD50 and APD80 was also observed.Compared to 10 ?mol/L epinephrine group,1 ?mol/L amiodarone+ 10 ?mol/L epinephrine significantly reduced VDD,RPF,Vmax,MDP and APA,lengthened APD50 and APD80.CONCLUSION:Amiodarone markedly decreases the autorhythmicity of the pacemaker cells in guinea-pig left ventricular outflow tract.This electrophysiological effects were significantly influenced by hypoxia,acidosis and epinephrine.
ABSTRACT
Objective To evaluate the therapeutic effect and safety of Lianhua Qingwen Capsules (LHQC) in the treatment of influenza. Methods A multi- center, randomized, double- blind, positive- controlled, parallel group trial was designed. A total of 240 cases, which were diagnosed with influenza and classified as the syndrome of toxic heat invading lung, aged from 18 to 50 years old, with body temperature over 38.0 ℃ and disease course with 48 hours, was recruited. The intent- to- treat infected (ITTI) population was 152 cases , among which 76 were treated with LHQC (4 capsules thrice daily for 3 days) and other 76 with Lingyang Ganmao Capsules (2 capsules thrice daily for 3 days). Results In the ITTI population, the effective rate for subsiding fever was 71.1 % and 53.9 % (P=0.029), and that for relieving TCM symptoms was 73.7 % and 55.3 % (P=0.018) in LHQC group and Lingyang Ganmao Capsules group, respectively. A safety analysis was conducted in 233 cases. No adverse action was found in LHQC group while two adverse events (allergic dermatitis and diarrhea) in Lingyang Ganmao Capsules group. Conclusion Early application of LHQC is effective and safe in treating infuenza.