AIM: To observe the effect of cestrum nocturnum n-butyl alcohol extract (CNAE) on contractile characteristics of right atrium
in isolated guinea pig and to probe into its possible pathway. METHODS: The experiment was completed at the Functional Laboratory of Gannan Medical College between June and September 2005. Breasts of eight guinea pigs were open to obtain heart to separated right atrium freely with eye scissors under lasting absorption of pure oxygen. Two ends were lined, ligated and put into Maclntyre bath tub. Then Krebs nutrient solution was added for keeping a certain degree of silent tension, temperature and pH value. Cumulative
administration and cross-reference method was adopted to detect effect of CNAE at mass concentrations of 0.1, 0.3, 1, 3, 10, 30 and 100 g/L on contractive amplitude, contractive velocity and diastolic velocity of isolated right atrium before and after administration with JZ100 tension converter. The values were recorded with Medlab-U/4CS biological signal collecting and processing system to calculate changing rates of contractive amplitude, contractive and diastolic velocities
. In addition, effect of CNAE on contraction of right atrium of isolated guinea pig was also analyzed. RESULTS: All 8 animals entered the final analysis without any loss. ① CNAE at low concentration (0.1 and 0.3 g/L) had mild effect on contractive amplitude of right atrium, but there was not significantly different; CNAE at 1 g/L improved the effect on contractive amplitude remarkably, and the increase rate was 15.2%; CNAE at high concentration (3, 10, 30 and 100 g/L) had negative concentration-dependent effect, and the inhibitory rates were 12.2%, 20.9%, 23.7% and 37.3% (P < 0.05-0.01). ② CNAE at low concentration (0.1, 0.3 and 1 g/L) had mild effect on contractive velocity of right atrium, but there was not significantly different; CNAE at high concentration (3, 10, 30 and 100 g/L) had negative concentration-dependent effect, especially the effects were obvious at concentrations of 10, 30 and 100 g/L, and the inhibitory rates were 19.6%, 33.5% and 53.4% (P < 0.05-0.01). ③ CNAE at low concentration (0.1, 0.3 and 1 g/L) had obvious effect on diastolic amplitude of right atrium, but there was not significantly different; CNAE at high concentration (3, 10, 30 and 100 g/L) had negative concentration-dependent effect, and the inhibitory rates were 6.75%, 19.11%, 20.36% and 41.64% (P < 0.05-0.01). CONCLUSION: CNAE at various concentrations has twofold regulation on contraction of right atrium in isolated guinea pig.