Perry E K, Gibson P H, Blessed G, Perry R H, Tomlinson B E
J Neurol Sci. 1977 Nov;34(2):247-65. doi: 10.1016/0022-510x(77)90073-9.
Reductions in 2 neurotransmitter synthesizing enzymes in brain, glutamic acid decarboxylase (GAD) and choline acetyltransferase (CAT), have been found in dementias of different origins, including senile dementia (Alzheimer type). Significant reductions in cerebral GAD have also been found in depression (unipolar). The GAD reductions did not generally appear to be localised in any specific region of the brain examined. However, the reduction of CAT in the hippocampus, relative to reductions in other areas examined, was substantially greater in the brains with Alzheimer-type changes. GAD and CAT activities in normal brains were examined for the effects of some variable factors inherent in necropsy biochemical measurements. These factors included: (i) age; (ii) agonal status; (iii) time of death, and (iv) delay in tissue sampling; and GAD was found to be significantly influenced by (ii), (iii) and (iv) and CAT by (i), (iii) and (iv). None of these factors accounted for the total alterations in the enzyme activities of the mentally abnormal brains. The results indicate that reductions in cerebral GAD require to be interpreted with caution in view of the sensitivity of this enzyme to premortem status but that reductions in cerebral CAT may be a more reliable index of pathological change in senile (Alzheimer-type) dementia.
在包括老年性痴呆（阿尔茨海默型）在内的不同病因的痴呆症患者大脑中，已发现两种神经递质合成酶——谷氨酸脱羧酶（GAD）和胆碱乙酰转移酶（CAT）减少。在抑郁症（单相抑郁）患者大脑中也发现GAD显著减少。一般来说，GAD的减少似乎并不局限于所检查大脑的任何特定区域。然而，相对于其他所检查区域的减少，在有阿尔茨海默型改变的大脑中，海马体中CAT的减少幅度要大得多。研究了正常大脑中GAD和CAT的活性，以探讨尸检生化测量中一些内在可变因素的影响。这些因素包括：（i）年龄；（ii）濒死状态；（iii）死亡时间，以及（iv）组织取样延迟；结果发现，GAD受（ii）、（iii）和（iv）显著影响，而CAT受（i）、（iii）和（iv）影响。这些因素均不能解释精神异常大脑中酶活性的全部变化。结果表明，鉴于GAD对死前状态的敏感性，大脑中GAD的减少需要谨慎解读，但大脑中CAT的减少可能是老年性（阿尔茨海默型）痴呆病理变化更可靠的指标。
