Pöpping S, Rose H, Ionescu I, Fischer Y, Kammermeier H
Institute of Physiology, Medical Faculty, Rheinisch-Westfälische Technische Hochschule, Aachen, Germany.
Arzneimittelforschung. 1995 Nov;45(11):1157-61.
The hawthorn extract LI 132 (crataegus), prepared from leaves and flowers, and standardised to 2.2% flavonoids, was investigated with respect to its effect on (1) the contraction, (2) the energy-turnover and (3) the apparent refractory period (t(ref)) of isolated cardiac myocytes from adult rats. (1) The contractile behaviour of attached myocytes was analyzed by an image processing system. (2) The energy turnover was calculated from the decrease in oxygen content in the myocyte suspension, brought about by cellular respiration. It was differentiated between energy turnover related to cell shortening and that required for ionic transport processes by application of the contraction-inhibiting agent 2,3-butanedione monoxime. (3) The apparent refractory period (t(ref)) was evaluated by pacing the myocytes with increasing stimulation rates and determining the frequency at which failure of single contractions occurred. For these purposes, the myocytes were incubated in a stimulation chamber, which is part of a computer-assisted system allowing to simultaneously evaluate the mechanics and energetics of electrically induced contraction. Within a range of 30-180 microg/ml, the hawthorn extract exhibited a positive inotropic effect on the contraction amplitude accompanied by a moderate increase of energy turnover both for mechanical and ionic processes. In comparison with other positive inotropic interventions, such as application of the beta-adrenergic agonist isoprenaline, or of the cardiac glycoside ouabain (g-strophantin), or elevation of the extracellular Ca++-concentration, the effects of the hawthorn extract were significantly more economical with respect to the energetics of the myocytes. Furthermore the extract prolonged the apparent refractory period in the presence and the absence of isoprenaline, which be indicative for an antiarrhythmic potential.
从山楂叶和花中制备的山楂提取物LI 132（山楂），其黄酮类化合物含量标准化为2.2%，研究了其对成年大鼠离体心肌细胞的（1）收缩、（2）能量转换和（3）有效不应期（t(ref)）的影响。（1）通过图像处理系统分析贴壁心肌细胞的收缩行为。（2）能量转换通过计算心肌细胞悬液中因细胞呼吸导致的氧含量下降来确定。通过应用收缩抑制剂2,3 - 丁二酮单肟区分与细胞缩短相关的能量转换和离子转运过程所需的能量转换。（3）通过以递增的刺激频率对心肌细胞进行起搏并确定单次收缩失败发生的频率来评估有效不应期（t(ref)）。为此，将心肌细胞置于刺激室中孵育，该刺激室是计算机辅助系统的一部分，可同时评估电诱导收缩的力学和能量学。在30 - 180微克/毫升的范围内，山楂提取物对收缩幅度表现出正性肌力作用，同时机械和离子过程的能量转换均适度增加。与其他正性肌力干预措施相比，如应用β - 肾上腺素能激动剂异丙肾上腺素、强心苷哇巴因（毒毛旋花子苷）或提高细胞外Ca++浓度，山楂提取物对心肌细胞能量学的影响显著更经济。此外，该提取物在有和没有异丙肾上腺素存在的情况下均延长了有效不应期，这表明其具有抗心律失常的潜力。
