Young A B
Department of Neurology and Neuroscience Program, University of Michigan, Ann Arbor.
J Neural Transm Suppl. 1987;24:147-52.
Amino acidergic neurons in the cerebral cortex are the most abundant neuronal types. The inhibitory amino acid, GABA, is the neurotransmitter of many cortical interneurons, particularly those in layers III and IV of cerebral cortex. The excitatory amino acids, glutamate and aspartate, are the likely neurotransmitters of corticofugal, corticocortical association and hippocampal pyramidal neurons. In dementia of the Alzheimer type (DAT), there is only mild to moderate loss of GABAergic neurons and there is only a mild reduction in postsynaptic GABAA receptors. The unique bicuculline-insensitive baclofen-sensitive GABAB receptor is affected in DAT and is reduced by about 60-70% in outer layers of cerebral cortex and hippocampus. Presynaptic markers of glutamate neurons (glutamate levels and glutamate sodium-dependent binding) are reduced 25-80% in cortex and hippocampus of DAT brain. Likewise, glutamate postsynaptic receptors, particularly the NMDA-sensitive receptor, are markedly reduced in DAT cortex and hippocampus. These alterations suggest that glutamatergic pyramidal cells are especially vulnerable in DAT brain.
大脑皮层中的氨基酸能神经元是最为丰富的神经元类型。抑制性氨基酸γ-氨基丁酸（GABA）是许多皮层中间神经元的神经递质，尤其是大脑皮层第III层和第IV层中的中间神经元。兴奋性氨基酸谷氨酸和天冬氨酸可能是皮质传出神经元、皮质-皮质联合神经元以及海马锥体细胞的神经递质。在阿尔茨海默型痴呆（DAT）中，GABA能神经元仅有轻度至中度缺失，突触后GABAA受体也仅有轻度减少。独特的荷包牡丹碱不敏感但巴氯芬敏感的GABAB受体在DAT中受到影响，在大脑皮层外层和海马中减少约60 - 70%。DAT脑的皮层和海马中，谷氨酸能神经元的突触前标记物（谷氨酸水平和谷氨酸钠依赖性结合）减少25 - 80%。同样，谷氨酸突触后受体，尤其是NMDA敏感受体，在DAT皮层和海马中显著减少。这些改变表明谷氨酸能锥体细胞在DAT脑中尤其脆弱。
