Erdmann E
Fortschr Med. 1979 Jul 5;97(25-26):1167-70.
Although the exact mechanism of positive inotropic action of cardiac glycosides is unknown, specific membrane bound proteins with high affinity for this group of drugs have been characterized. These "receptors" for cardiac glycosides have been measured quantitatively in cardiac tissue of humans and several species as well as in other tissues. The occupation of receptors by cardioactive steroids has been found to agree quantitatively with the drug effects in respect to inhibition of (Na+ + K+)-ATPase and in respect to positive inotropy (these experiments were performed in electrically stimulated contracting cardiac muscle). Changes in receptor concentration or receptor properties have been observed in hyperthyroidism, chronic hypokalaemia, thalassaemia or in acutely changed serum concentrations of K+, Ca++ and several drugs. These changes may be of great significance in patients treated with cardiac glycosides as their effects are not reflected by the serum concentration of cardiac glycosides. The understanding of drug-receptor-interactions on the molecular level--especially under the pathological conditions in the patient--will increase our diagnostic and therapeutic knowledge.
虽然强心苷正性肌力作用的确切机制尚不清楚，但已鉴定出对这类药物具有高亲和力的特定膜结合蛋白。已在人类和几种物种的心脏组织以及其他组织中对这些强心苷“受体”进行了定量测定。已发现，强心甾类占据受体的情况在抑制（Na+ + K+）-ATP酶方面以及在正性肌力作用方面（这些实验是在电刺激收缩的心肌中进行的）与药物效应在数量上相符。在甲状腺功能亢进、慢性低钾血症、地中海贫血或血清中K+、Ca++浓度以及几种药物浓度急性改变时，已观察到受体浓度或受体特性的变化。这些变化在用强心苷治疗的患者中可能具有重要意义，因为强心苷的血清浓度并不能反映其效应。在分子水平上理解药物-受体相互作用——尤其是在患者的病理状况下——将增加我们的诊断和治疗知识。
