Fischer W, Müller M, Jordan D
Acta Biol Med Ger. 1980;39(4):461-7.
In preparations of the isolated guinea-pig ileum 2,3-dioxoindoline shows a dose-dependent stimulating activity. In a contraction range between 5 x 10(-5) to 2 x 10(-3) moles/l this compound is spasmogenic and causes concentration (pD2 = 3.3). Prolonged contact time of higher concentrations of isatin results in a reduction of excitation and a relaxation of the ileum. An additive synergism is seen in combined treatment with serotonin. Pretreatment with serotonin antagonists reduces the stimulating effect of isatin. Quantitative differences in inhibition by dihydroergotamine and benzyloxygramine in contrast to morphine or atropine actions provided evidence that the stimulating activity of isatin is mainly mediated through the "D" receptors on the smooth muscle cells. Besides its stimulating effect isatin also exhibits blocking activity when tested against 5-HT (ACh). In high concentration (> 2 mmoles/l) isatin is able to antagonize--after only 2 min of pre-incubation--responses to 5-HT completely. In this range dose-response curves become progressively flatter and their maxima decline in a non-competitive way.
在离体豚鼠回肠制备物中，2,3 - 二氧代吲哚啉呈现出剂量依赖性的刺激活性。在5×10⁻⁵至2×10⁻³摩尔/升的收缩范围内，该化合物具有致痉作用并引起浓度效应（pD2 = 3.3）。较高浓度的异吲哚酮延长接触时间会导致兴奋性降低和回肠松弛。与血清素联合治疗时可见相加协同作用。血清素拮抗剂预处理可降低异吲哚酮的刺激作用。与吗啡或阿托品作用相比，二氢麦角胺和苄氧基格拉明抑制作用的定量差异表明，异吲哚酮的刺激活性主要通过平滑肌细胞上的“D”受体介导。除了其刺激作用外，异吲哚酮在针对5 - HT（乙酰胆碱）进行测试时也表现出阻断活性。在高浓度（> 2毫摩尔/升）下，异吲哚酮仅预孵育2分钟就能完全拮抗对5 - HT的反应。在此范围内，剂量 - 反应曲线逐渐变平，其最大值以非竞争性方式下降。
