Valcana T, Hudson D B, Timiras P S
Neurochem Res. 1984 Oct;9(10):1533-42. doi: 10.1007/BF00964679.
X-irradiation of the rat brain (1000R, at two days of age), suppresses the normal age-related increase in the weight of the cerebellum and cerebral hemispheres and influences amino acid levels. The decrease in glutamic acid concentration, particularly in the cerebellum, supports the previously advanced proposition that this amino acid may be associated with or may be the transmitter of, the rat cerebellar granule cells. Subfractionation of the cerebellar tissue reveals that the decrease in the glutamic acid level consequent to the loss of granule cells, is reflected in the cytoplasmic fraction but not in the synaptic vesicle subfraction, where glutamic acid was increased. The reduced weight gain in the cerebral hemispheres after irradiation, is accompanied by a significant decrease of aspartate in the cytoplasmic fraction, changes which suggest that a specific cell type, with aspartic acid as its neurotransmitter (possibly in the hippocampus), may also be radiosensitive in the early postnatal period. In contrast, in the synaptic vesicle fraction from cerebral hemispheres, all free amino acids, with the exception of glutamine, increased significantly. Overall, the changes in free amino acid concentration induced by X-irradiation in the cytoplasmic fraction in both brain regions studied are opposite to those found in the synaptic vesicle fraction and although they may indicate changes in specific cell populations, as proposed above, they could also reflect changes in cellular compartmentalization and metabolism or changes in the relative axonal arborization of the affected regions.
对出生两天的大鼠脑部进行X射线照射（1000伦琴），会抑制小脑和大脑半球重量随年龄正常增加，并影响氨基酸水平。谷氨酸浓度降低，尤其是在小脑中，支持了之前提出的观点，即这种氨基酸可能与大鼠小脑颗粒细胞相关，或者可能是其递质。对小脑组织进行亚分级分离显示，由于颗粒细胞丢失导致的谷氨酸水平降低，在细胞质部分有所体现，但在突触小泡亚分级部分未体现，在该部分谷氨酸含量增加。照射后大脑半球体重增加减少，同时细胞质部分天冬氨酸显著减少，这些变化表明，一种以天冬氨酸作为神经递质的特定细胞类型（可能在海马体中），在出生后早期可能也对辐射敏感。相比之下，在大脑半球的突触小泡部分，除谷氨酰胺外，所有游离氨基酸均显著增加。总体而言，在所研究的两个脑区的细胞质部分，X射线照射诱导的游离氨基酸浓度变化与突触小泡部分相反，尽管如上文所述，它们可能表明特定细胞群体的变化，但也可能反映细胞区室化和代谢的变化，或受影响区域相对轴突分支的变化。
