SPECT IMAGING OF STRIATAL DOPAMINE WITH (123I)IBZM, RESERPINE AND AMPT

内源性多巴胺对体内D2受体测定的影响 通过9名健康志愿者的比较， [123 I '] IBZM在急性多巴胺中毒前后的结合电位（BP） 耗尽多巴胺耗竭是通过给予 酪氨酸羟化酶抑制剂α-甲基-对-酪氨酸（AMPT，1 g QID 两天）。 AMPT使[123 I]IBZM增加28 ± 16%（平均值+ DS，n=9）。 在啮齿类动物身上进行的具有类似时间进程的实验表明， 是由于内源性多巴胺的清除，而不是D2受体 上调。 因此，D2受体被多巴胺显著占据 处于静止状态。 这种模式将扩展到 明年对精神分裂症患者进行评估， 与健康人相比，多巴胺的基础D2占用水平异常 科目

The impact of endogenous dopamine on in vivo measurement of D2 receptors in humans was evaluated with SPECT by comparing in 9 healthy volunteers the binding potenial (BP) of [123I']IBZM before and after acute dopamine depletion. Dopamine depletion was achieved by administration of the tyrosine hydorxylase inhimitor alpha-methyl-para-tyrosine (AMPT, 1 g QID for two days). AMPT increased [123I]IBZM by 28+16% (mean + DS,n=9). Experiments in rodents with a similar time course showed that this effect was due to removal of endogenous dopamaine rather D2 receptor upregulation. Thus, D2 receptors are significantly occupied by dopamine in the resting state in humans. This paradigm will be extended over the next year to patients with schizophrenia to assess whether patients have an abnormal level of basal D2 occupancy by dopamine compared to healthy subjects.