花椒毒酚对豚鼠离体心房肌生理特性的影响

目的 研究花椒毒酚对豚鼠离体心肌生理特性的影响。 方法 采用豚鼠离体心房, 测定花椒毒酚对豚鼠心房率, 心肌收缩力, 左心房的兴奋性的影响。 结果 在心肌收缩力的实验中, 给花椒毒酚20,40, 80 μmol·L^-1 15 min后, 左心房的收缩力分别为0.85、0.68、0.48 g, 与对照组比较, 花椒毒酚明显抑制豚鼠左心房肌的收缩力(P <0.05), 并呈浓度依赖性;在对心房率的实验中, 给花椒毒酚20,40 μmol·L^-1, 30 min 后, 离体右心房的频率从90.0 次·min^-1分别下降至60.2、38.7 次·min^-1, 与对照组比较有显著的统计学意义(P <0.05);花椒毒酚对豚鼠左心房的功能性不应期和左心房兴奋性无明显影响。 结论 花椒毒酚可以降低心房自律性、抑制心房收缩力, 其负性变频和负性变力效应可能与其抑制心肌细胞外钙内流和内钙释放有关。

Effects of xanthotoxol on physiological characteristics of isolated guinea pig atrium

AIM: To study the effects of xanthotoxol (XT) on physiological characteristics and its mechanism in isolated guinea pig atria. METHODS: It was determined by the contractile amplitude, excitability and the spontaneous beats in the right atria, respectively. RESULTS: In the experiment of contractile amplitude, after 15 min of administration of XT 20, 40 and 80 μmol·L^-1, the contractile force of left atria was 0.85, 0.68, and 0.48 g, respectively (P <0.05, compared with control group).It showed that XT could decrease the contractile force in concentration-dependent manner significantly.In the experiment of the sinus rates, after 30 min of administration of XT 20 and 40 μmol·L^-1, the fact that the sinus rates decreased from 90.0 min-1 to 60.2 min-1 and 38.7 min-1, respectively (P <0.05 vs solvent group) indicated that XT significantly reduced the sinus rates.In the experiments of the functional refractory period and excitability, no effects of XT were demonstrated. CONCLUSION: XT can decrease the contractile force and the spontaneous beats.The inotropic and chronotropic action of XT may be related to inhibiting Ca²⁺ influx from outside the cells and Ca 2+ release from calcium reservoir inside the cells.