Erdmann E
Arzneimittelforschung. 1985;35(12A):1948-52.
The receptor for cardiac glycosides probably is identical with the (Na+ + K+)-ATPase (approximately 250 000 Daltons). Its affinity for the therapeutically used glycosides is extremely different in different species (KD approximately 10(-9)M (human heart) - approximately 10(-7)M (rat heart]. In the latter, two distinct receptor types have been demonstrated (high- and low-affinity receptors) with different effects. In the human heart, there may be two cardiac glycoside receptors as well, although this has not been proved as yet. The number of cardiac glycoside receptors and their affinity is regulated in certain states and diseases. An increased receptor density is found in hyperthyroid states, in chronic hypokalaemia and in chronic digitalis treatment. A decreased number is measured in ischemic heart disease, in dilated cardiomyopathy and in hypothyroidism. Parallel to the decreased receptor density the maximal cardiac glycoside induced positive inotropy is reduced. Pronounced toxicity occurs, if the digitalis dose is increased in spite of missing effects.
强心苷受体可能与（钠+钾）-ATP酶（约250000道尔顿）相同。其对治疗用苷类的亲和力在不同物种中差异极大（解离常数KD约为10⁻⁹M（人类心脏）-约10⁻⁷M（大鼠心脏））。在大鼠心脏中，已证实存在两种不同类型的受体（高亲和力和低亲和力受体），且具有不同的效应。在人类心脏中，可能也存在两种强心苷受体，尽管尚未得到证实。强心苷受体的数量及其亲和力在某些状态和疾病中会受到调节。在甲状腺功能亢进状态、慢性低钾血症和慢性洋地黄治疗中，受体密度会增加。在缺血性心脏病、扩张型心肌病和甲状腺功能减退症中，受体数量会减少。与受体密度降低并行的是，强心苷诱导的最大正性肌力作用会减弱。如果尽管没有效果却仍增加洋地黄剂量，就会出现明显的毒性。
