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目的:观察高功率微波辐射对大鼠脑内氨基酸类神经递质及全身儿茶酚胺代谢的影响。方法:实验于2004-09/12解放军军事医学科学院放射与辐射医学研究所实验病理研究室完成。选择6～8周二级雄性Wistar大鼠60只,随机抽签法分为假辐射组(n=10)和辐射组(n=50)。辐射组按照辐射剂量分为3mW/cm2亚组(n=10)、10mW/cm2亚组(n=20)、30mW/cm2亚组(n=10)和100mW/cm2亚组(n=10)。采用0,3,10,30和100mW/cm2高功率微波辐射大鼠,于辐射后6h、1d和7d活杀取材,通过高效液相色谱仪检测大脑皮质、海马和丘脑中谷氨酸、天冬氨酸、γ-氨基丁酸和甘氨酸4种氨基酸的含量以及尿中香草扁桃酸和高香草酸含量的变化。结果:参加实验大鼠60只,均进入结果分析。①高功率微波辐射后6h大鼠不同脑区氨基酸类神经递质含量的变化:大脑皮质,10mW/cm2组谷氨酸及γ-氨基丁酸含量升高,谷氨酸/γ-氨基丁酸比值降低;海马3～100mW/cm2组谷氨酸含量均显著降低。丘脑中4种氨基酸含量无明显改变。②高功率微波10mW/cm2辐射不同时间后大鼠不同脑区氨基酸类神经递质含量的变化:辐射后6h大脑皮质谷氨酸含量升高,1d后基本恢复正常;γ-氨基丁酸含量明显升高,1d后有所恢复,7d时仍未恢复正常;谷氨酸/γ-氨基丁酸比值显著降低,1d后有所恢复,7d时仍未恢复正常。海马内谷氨酸含量明显降低;甘氨酸含量在辐射后6h明显降低,1d时基本恢复。丘脑氨基酸含量无明显改变。③高功率微波辐射后尿中儿茶酚胺代谢产物含量的变化:辐射后3d,10mW/cm2组尿中香草扁桃酸含量显著升高,30和100mW/cm2组显著降低;10mW/cm2组尿中高香草酸含量于显著降低;而100mW/cm2组显著升高。结论:高功率微波辐射可引起大鼠氨基酸类和儿茶酚胺类神经递质代谢紊乱,大脑皮质和丘脑均可见主要兴奋性和抑制性氨基酸含量升高,二者比值下降,提示兴奋性氨基酸参与了大脑皮质和丘脑的早期损伤,而抑制性氨基酸则与其病变恢复有关。海马兴奋性氨基酸含量及谷氨酸/γ-氨基丁酸比值均降低,提示海马神经元的兴奋性降低,可能与学习记忆能力的降低密切相关。
Objective: To observe the effect of high power microwave radiation on amino acid neurotransmitters and catecholamine metabolism in rat brain. METHODS: The experiment was performed at the Laboratory of Pathology, Institute of Radiation Medicine and Radiation Medicine, PLA Academy of Military Medical Sciences. Sixty male Wistar rats aged 6 to 8 weeks were selected and randomly divided into sham irradiation group (n = 10) and radiation group (n = 50). The radiation group was divided into 3mW / cm2 subgroup (n = 10), 10mW / cm2 subgroup (n = 20), 30mW / cm2 subgroup (n = 10) and 100mW / cm2 subgroup . The rats were irradiated with high power microwaves of 0, 3, 10, 30 and 100mW / cm2, and killed at 6h, 1d and 7d after irradiation. The contents of glutamate in cerebral cortex, hippocampus and thalamus were detected by high performance liquid chromatography Amino acids, γ-aminobutyric acid and glycine, and the content of vanilloid mandelic acid and vanillic acid in urine. Results: Sixty experimental rats participated in the result analysis. (1) Changes of amino acid neurotransmitters in different brain regions of rats at 6h after high-power microwave irradiation: In the cerebral cortex, glutamic acid and γ-aminobutyric acid increased at 10mW / cm2, glutamate / γ- The ratio of glutamate decreased in hippocampus 3 ~ 100mW / cm2 group. There was no significant change in the contents of 4 kinds of amino acids in thalamus. (2) Changes of amino acid neurotransmitters in different brain regions of rats exposed to 10 mW / cm2 of high power microwave radiation for 6 days: the content of glutamate in cerebral cortex increased 6 h after radiation and returned to normal after 1 d; the content of γ-aminobutyric acid After 1 day, it returned to normal level, and still not returned to normal after 7 days. The ratio of glutamic acid / γ-aminobutyric acid decreased significantly after 1 day, and returned to normal after 7 days. The content of glutamic acid in hippocampus decreased obviously; the content of glycine decreased significantly at 6h after radiation and recovered basically on the 1st day. Thalamus amino acid content no significant change. (3) The changes of urinary catecholamine metabolites after high power microwave irradiation: The content of vanilloid mannitol in urine of 10mW / cm2 group increased significantly at 3d after radiation and decreased significantly in 30 and 100mW / cm2 group; Content significantly decreased; while 100mW / cm2 group was significantly increased. Conclusion: High-power microwave radiation can cause metabolic disorder of amino acids and catecholamine neurotransmitter in rats. The main excitatory and inhibitory amino acid contents in both cerebral cortex and thalamus are both increased, and the ratio of the two is decreased, suggesting that excitatory amino acids are involved in the brain Cortical and thalamic early damage, while the inhibitory amino acids are associated with its recovery. Excitatory amino acid content and glutamic acid / γ-aminobutyric acid ratio in hippocampus decreased, suggesting that the excitability of hippocampal neurons decreased, which may be closely related to the decrease of learning and memory ability.