Inarejo M, Himmel H, Ravens U
Pharmakologisches Institut, Universitätsklinikum, Essen, Germany.
Arch Int Pharmacodyn Ther. 1993 May-Jun;323:50-61.
The inotropic effects of isoprenaline, dobutamine and dopexamine were studied in human right atrial myocardium and in rat and guinea-pig left atria electrically stimulated at 1 Hz. To investigate the contribution of endogenously released catecholamines to the positive inotropic effects of beta-adrenoceptor agonists, experiments were performed both in the absence and in the presence of the uptake inhibitors desipramine and corticosterone. In all three species, the maximum positive inotropic responses to isoprenaline and dobutamine were not influenced by the pretreatment, whereas the responses to dopexamine were modified, i.e. the maximum force increase was reduced and the concentration-response curves were shifted to the right. After uptake inhibition, the decrease in positive inotropic action of dopexamine was largest in rat atria followed by guinea-pig and human atria. It is concluded that, in the untreated atrial muscle from all three species, endogenous catecholamines contribute only to the inotropic responses of dopexamine but not to those of isoprenaline or dobutamine.
在1Hz电刺激下，研究了异丙肾上腺素、多巴酚丁胺和多培沙明对人心房肌以及大鼠和豚鼠左心房的变力作用。为了研究内源性释放的儿茶酚胺对β-肾上腺素能受体激动剂正性变力作用的贡献，在不存在和存在摄取抑制剂地昔帕明和皮质酮的情况下进行了实验。在所有三个物种中，对异丙肾上腺素和多巴酚丁胺的最大正性变力反应不受预处理的影响，而对多培沙明的反应则有所改变，即最大力增加降低，浓度-反应曲线右移。摄取抑制后，多培沙明正性变力作用的降低在大鼠心房中最大，其次是豚鼠和人心房。结论是，在所有三个物种未经处理的心房肌中，内源性儿茶酚胺仅对多培沙明的变力反应有贡献，而对异丙肾上腺素或多巴酚丁胺的变力反应无贡献。
