Kemppainen N, Laine M, Laakso M P, Kaasinen V, Någren K, Vahlberg T, Kurki T, Rinne J O
Department of Neurology, PO Box 52, University of Turku, FIN-20521 Turku, Finland.
Eur J Neurosci. 2003 Jul;18(1):149-54. doi: 10.1046/j.1460-9568.2003.02716.x.
Post mortem studies have revealed a loss of dopamine D2 receptors in the temporal lobes in Alzheimer's disease (AD). Moreover, the role of hippocampal D2 receptors on memory performance has been suggested in experimental studies. However, there are no previous in vivo studies on extrastriatal D2 receptors in AD. Our aim was to examine in vivo whether hippocampal or temporal cortical dopamine D2 receptors are affected in AD and whether D2 receptor availability is associated with the memory dysfunction seen in AD. Fourteen patients with probable AD and 11 age- and sex-matched controls were studied with positron emission tomography using a dopamine D2/D3 receptor antagonist [(11)C]FLB 457. The D2 receptor binding potentials (BPs) were measured in extrastriatal brain regions and a neuropsychological investigation was performed on the patients with AD. In AD, the D2 receptor availability was reduced in the hippocampus: by 34% (P = 0.03) in the right hippocampus and by 14% (P = 0.78) in the left hippocampus as compared with controls. Multiple linear regression analysis showed that the BP in the right hippocampus had a significant positive association with verbal memory performance (Wechsler Memory Scale - Revised) (P = 0.001) and picture naming (the Boston Naming Test) (P = 0.002). Our findings suggest a role for temporal lobe D2 receptors in the memory and naming performance in AD, and suggest that studies to evaluate the efficiency of dopaminergic medication on patients with early AD might be warranted.
尸检研究显示，阿尔茨海默病（AD）患者颞叶中的多巴胺D2受体减少。此外，实验研究表明海马体D2受体在记忆表现中发挥作用。然而，此前尚无关于AD患者纹状体以外区域D2受体的体内研究。我们的目的是在体内研究AD患者海马体或颞叶皮质中的多巴胺D2受体是否受到影响，以及D2受体可用性是否与AD患者出现的记忆功能障碍相关。使用多巴胺D2/D3受体拮抗剂[(11)C]FLB 457，通过正电子发射断层扫描对14例可能患有AD的患者以及11名年龄和性别匹配的对照者进行了研究。在纹状体以外的脑区测量D2受体结合势（BP），并对AD患者进行了神经心理学调查。在AD患者中，海马体中的D2受体可用性降低：右侧海马体降低了34%（P = 0.03），左侧海马体降低了14%（P = 0.78），与对照组相比。多元线性回归分析表明，右侧海马体中的BP与言语记忆表现（韦氏记忆量表修订版）（P = 0.001）和图片命名（波士顿命名测试）（P = 0.002）呈显著正相关。我们的研究结果表明颞叶D2受体在AD患者的记忆和命名表现中发挥作用，并表明可能有必要开展研究来评估多巴胺能药物对早期AD患者的疗效。
