World Wide Discovery Research, Cephalon, Inc., West Chester, PA 19380, USA.
J Neurosci Methods. 2009 Dec 15;185(1):70-5. doi: 10.1016/j.jneumeth.2009.09.015. Epub 2009 Sep 16.
Histamine H(3) receptor antagonists have been proposed as a novel approach to the treatment of cognitive, attentional, and sleep disorders. It is apparent that H(3) receptor antagonists produce in vivo effects in preclinical animal models of central diseases across a wide dose range. In order to characterize the relationship between efficacy in the preclinical models and H(3) receptor occupancy, a brain slice receptor autoradiography method was used. Brain slice receptor autoradiography requires less in vitro tissue processing, preserves brain structure, and provides anatomical localization of compound in the brain. Consistent with H(3) receptor distribution, in vitro autoradiography experiments demonstrated specific binding of [(3)H]NAMH (N-alpha-methylhistamine) in rat cortex, and other brain regions, but not in cerebellum. Ex vivo H(3)R brain slice autoradiography was able to detect H(3) receptor occupancy by reference antagonists at doses lower than previously found using a homogenate assay format. The method is relatively quick with image acquisition on a beta-imager and is capable of detecting receptor occupancy in different brain regions simultaneously. Furthermore, the increased sensitivity should be useful in providing dosing guidelines for H(3) antagonists in both preclinical and clinical settings.
组胺 H（3）受体拮抗剂被认为是治疗认知、注意力和睡眠障碍的一种新方法。显然，H（3）受体拮抗剂在中枢疾病的临床前动物模型中，在很宽的剂量范围内产生体内效应。为了描述临床前模型中的疗效与 H（3）受体占有率之间的关系，采用了脑切片受体放射自显影方法。脑切片受体放射自显影需要较少的体外组织处理，保留了脑结构，并提供了化合物在脑内的解剖定位。与 H（3）受体分布一致，体外放射自显影实验表明，[（3）H]NAMH（N-α-甲基组氨酸）在大鼠皮质和其他脑区特异性结合，但不在小脑结合。通过参考拮抗剂，在体外 H（3）R 脑切片放射自显影中，能够检测到比以前在匀浆测定中发现的更低剂量的 H（3）受体占有率。该方法相对较快，在β-成像仪上进行图像采集，并能够同时检测不同脑区的受体占有率。此外，增加的灵敏度应该有助于为 H（3）拮抗剂在临床前和临床环境中的给药提供指导。
