Videbaek C, Andersen J V, Dalgaard L, Foged C, Paulson O B, Lassen A N
Department of Neurology, National University Hospital, Rigshospitalet, Copenhagen, Denmark.
Eur J Pharmacol. 1995 Aug 4;281(2):117-22. doi: 10.1016/0014-2999(95)00205-y.
A steady state method for neuroreceptor quantification in vivo in small laboratory animals is described, using [123I]iomazenil as tracer for the benzodiazepine receptor. The method was used for determination of the receptor equilibrium constant for a non-radioactive ligand, flumazenil, in rats and involved measurement of the nonspecific binding of [123I]iomazenil. Thirty-five animals were intravenously infused for 2 h with [123I]iomazenil and flumazenil in different proportions to obtain occupancies of the benzodiazepine receptor from close to 0 to about 99%. The nonspecific binding of iomazenil in brain tissue was calculated by an iterative procedure from the data for the highly blocked animals, and it was found to be 1.04 ml per ml plasma (n = 6). The mean cortical Kd of flumazenil was 21 +/- 11 nM (n = 19). The method is discussed with special reference to the problems of ascertaining steady state and nonspecific binding.
描述了一种在小型实验动物体内进行神经受体定量的稳态方法，使用[123I]异氟烷作为苯二氮䓬受体的示踪剂。该方法用于测定大鼠体内非放射性配体氟马西尼的受体平衡常数，涉及测量[123I]异氟烷的非特异性结合。35只动物静脉注射[123I]异氟烷和氟马西尼不同比例的混合液2小时，以获得苯二氮䓬受体从接近0%到约99%的占有率。通过对高度阻断动物的数据进行迭代计算，得出脑组织中异氟烷的非特异性结合量为每毫升血浆1.04毫升（n = 6）。氟马西尼的平均皮质解离常数（Kd）为21±11 nM（n = 19）。特别针对确定稳态和非特异性结合的问题对该方法进行了讨论。
