苗药黑骨藤醇提物乙酸乙酯部位对离体蛙心功能的影响

目的:研究黑骨藤醇提物乙酸乙酯部位对离体蛙心功能的影响,并对其可能的作用机制进行初步考察。方法:采用斯氏蛙心插管法制备离体蛙心标本,分别用任氏液(空白对照)和质量浓度为1.74、3.48 mg/mL的黑骨藤醇提物乙酸乙酯部位进行灌流,用BL-420生物机能实验系统记录离体心脏的心率和心肌收缩力变化,以考察黑骨藤醇提物乙酸乙酯部位对离体蛙心功能的影响。先分别用10 mg/L的阿托品、异丙肾上腺素20μL或1μL低钙(每1 000 mL纯水中含CaCl20.06 g)、高钙(每1 000 mL纯水中含CaCl20.24 g)任氏液进行灌流,然后再分别加入1.74 mg/mL的黑骨藤醇提物乙酸乙酯部位,用BL-420生物机能实验系统记录离体心脏的心肌收缩力变化;并取用任氏液(空白对照)和质量浓度为1.74、3.48 mg/mL的黑骨藤醇提物乙酸乙酯部位灌流后的心肌组织,测定其中Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶和乙酰胆碱酯酶(AChE)活性,以考察黑骨藤醇提物乙酸乙酯部位影响心脏功能的可能作用机制。结果:加入质量浓度为1.74、3.48 mg/mL黑骨藤醇提物乙酸乙酯部位后,蛙心的心肌平均收缩力较空白对照明显降低(P<0.001),但心率的变化不明显(P>0.05)。随着细胞外Ca2+浓度的逐渐增大,黑骨藤醇提物乙酸乙酯部位对离体蛙心收缩的抑制作用也逐渐增大;加入阿托品、异丙肾上腺素后,黑骨藤醇提物乙酸乙酯部位对离体蛙心收缩的抑制作用有所降低;经过1.74、3.48 mg/mL黑骨藤醇提物乙酸乙酯部位灌流后的蛙心心肌组织中Na+-K+-ATP酶活性较空白对照改变不明显(P>0.05),但Ca2+-Mg2+-ATP酶活性明显升高(P<0.05)、AChE活性明显降低(P<0.05)。结论:黑骨藤醇提物乙酸乙酯部位可抑制离体蛙心的收缩活动,具有一定的负性肌力作用;其作用机制可能与提高心肌组织中Ca2+-Mg2+-ATP酶活性,抑制AChE活性,同时阻断细胞膜上Ca2+通道,兴奋M受体和阻断β受体有关。

Effects of Ethyl Acetate Part from Ethanol Extract of Miao Medicine Periploca forrestii on Cardiac Function of Isolated Frog Heart

OBJECTIVE:To study the effects of ethyl acetate part form the ethanol extract of Periploca forrestii on cardiac function of isolated frog heart,and to primarily investigate its potential mechanism. METHODS:The isolated frog heart samples were prepared by using the intube method of steinmann. The Ren’s solution(blank control),1.70 mg/m L and 3.48 mg/m L ethyl acetate part from ethanol extract of P. forrestii were used to perfuse the sample. The BL-420 biological function experimental system was used to record the changes in heart rate and myocardial contractility. The effects of ethyl acetate part from ethanol extract of P. forrestii on cardiac function of isolated frog heart were investigated. After perfused with 10 mg/L atropine,20 μL isoproterenol,1 μL low calcium(per 1 000 m L pure water contain 0.06 g CaCl2),high calcium Ren’s solution(per 1 000 m L pure water contain 0.24 g CaCl2),adding 1.74 mg/m L ethyl acetate part from ethanol extract of P. forrestii,the changes of myocardial contractility in isolated hearts were recorded by BL-420 biological function experimental system. Myocardial tissue was collected after perfused with Ren’s solution(blank control) and ethyl acetate part from ethanol extract of P. forrestii with 1.74 and 3.48 mg/m L. The activity of Na+-K+-ATPase, Ca2+-Mg2+-ATPase and ACh E were detected to investigate the potential mechanism of the effects of ethyl acetate extract from ethanol extract of P. forrestii on cardiac function. RESULTS: Compared with blank control, mean myocardial contractility was significantly decreased(P<0.001)after adding 1.74,3.48 mg/m L ethyl acetate part form ethanol extract of P. forrestii,but had no significant on heart rate(P>0.05). With the increase of extracellular Ca2+concentration,the inhibitory effect of ethyl acetate part from ethanol extract of P. forrestii on isolated frog heart contraction also increased gradually. After adding atropine and isoproterenol,the inhibitory effect of the ethyl acetate part form ethanol extract of P. forrestii on isolated frog heart contraction decreased to some certain. The activity of Na+-K+-ATPase in cardiac tissue was not significantly changed(P>0.05),the activity of Ca2+-Mg2+-ATPase was significantly increased(P<0.05),and the activity of ACh E was significantly decreased(P<0.05)after perfused with 1.74,3.48 mg/m L ethyl acetate part form ethanol extract of P. forrestii. CONCLUSIONS:The ethyl acetate part from the ethanol extract of P. forrestii can inhibit the contractile activity of the isolated frog heart and has a certain negative inotropic effect. The mechanism may be related to the increase of Ca2+-Mg2+-ATPase activity,inhibition of ACh E activity,blocking of calcium channel in the cell membrane,the activation of M receptor and blocking of β receptor.