Kung H F, Pan S, Kung M P, Billings J, Kasliwal R, Reilley J, Alavi A
Department of Radiology, University of Pennsylvania, Philadelphia 19104.
J Nucl Med. 1989 Jan;30(1):88-92.
In vitro binding characteristics of a CNS dopamine D-2 receptor imaging agent, (S)-N-[(1-ethyl-2-pyrrolidinyl)] methyl-2-hydroxy-3-iodo-6-methoxybenzamide [( 125I]IBZM), was carried out in rats. Also brain images, as well as organ biodistribution were determined in a monkey following the administration of 123I-labeled compound. The S-(-)-I[125I]IBZM showed high specific dopamine D-2 receptor binding in rat striatum (Kd = 0.426 +/- 0.082 nM, Bmax = 480 +/- 22 fmol/mg of protein). Competition of various ligands for the IBZM binding displayed the following rank order of potency: spiperone greater than S(-)IBZM much greater than R(+)IBZM greater than or equal to S(-)BZM greater than dopamine greater than ketanserin greater than SCH-23390 much greater than propranolol, norepinephrine, serotonin. In vivo planar images of a monkey injected with [123I]IBZM demonstrated a high concentration in basal ganglia of brain. The ratios of activity in the basal ganglia to cerebellum and the cortex to cerebellum in monkey brain were 4.93 and 1.44, respectively, at 120 min postinjection. These preliminary results indicate that [123I]IBZM is a potentially promising imaging agent for the investigation of dopamine D-2 receptors in humans.
在大鼠体内进行了一种中枢神经系统多巴胺D-2受体显像剂，即(S)-N-[(1-乙基-2-吡咯烷基)]甲基-2-羟基-3-碘-6-甲氧基苯甲酰胺([125I]IBZM)的体外结合特性研究。同时，在给猴子注射123I标记的化合物后，测定了其脑图像以及器官生物分布。S-(-)-I[125I]IBZM在大鼠纹状体中显示出高特异性多巴胺D-2受体结合(Kd = 0.426±0.082 nM，Bmax = 480±22 fmol/mg蛋白质)。各种配体对IBZM结合的竞争显示出以下效价顺序：螺哌隆大于S(-)IBZM远大于R(+)IBZM大于或等于S(-)BZM大于多巴胺大于酮色林大于SCH-23390远大于普萘洛尔、去甲肾上腺素、血清素。给猴子注射[123I]IBZM后的体内平面图像显示脑基底神经节中有高浓度。注射后120分钟时，猴子脑内基底神经节与小脑的活性比以及皮质与小脑的活性比分别为4.93和1.44。这些初步结果表明，[123I]IBZM是一种用于研究人类多巴胺D-2受体的潜在有前景的显像剂。
