Kontur P J, Fechter L D
Department of Environmental Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205.
Neurotoxicol Teratol. 1988 Jul-Aug;10(4):295-303. doi: 10.1016/0892-0362(88)90031-1.
The brain distribution of manganese (Mn) and the regional steady state levels of monoamines and their metabolites in normal and Mn-treated neonatal rats have been investigated. Neonatal rats were intubated daily with distilled water, 25 or 50 micrograms manganous chloride/g/day for 14 or 21 days. Manganese levels in brain regions and liver were analyzed by flameless atomic absorption spectroscopy. Norepinephrine, dopamine, serotonin and their metabolites in the striatum, hypothalamus, and nucleus accumbens were analyzed by HPLC. The levels of Mn in Mn-treated animals were increased at 14 and 21 days of age although brain levels at 21 days were lower than those at 14 days. Monoamine and metabolite levels were not altered by Mn treatment in any region at either age. Thus, increases in brain Mn levels do not necessarily result in alterations in steady state neurotransmitter and metabolite levels. These results suggest that the neurotoxic effects of these doses of Mn administered to neonatal animals are not expressed as alterations in steady state levels of monoamines and metabolites. The developing nervous system may be able to compensate for neurochemical changes caused by Mn exposure.
已对正常新生大鼠和经锰处理的新生大鼠体内锰（Mn）的脑部分布以及单胺及其代谢产物的区域稳态水平进行了研究。新生大鼠每日经插管给予蒸馏水、25或50微克氯化锰/克/天，持续14或21天。采用无火焰原子吸收光谱法分析脑区和肝脏中的锰水平。通过高效液相色谱法分析纹状体、下丘脑和伏隔核中的去甲肾上腺素、多巴胺、5-羟色胺及其代谢产物。经锰处理的动物在14日龄和21日龄时锰水平升高，尽管21日龄时的脑内水平低于14日龄时。在任何一个年龄段，经锰处理均未改变任何区域的单胺和代谢产物水平。因此，脑内锰水平的升高不一定会导致稳态神经递质和代谢产物水平的改变。这些结果表明，给予新生动物这些剂量的锰所产生的神经毒性作用并未表现为单胺和代谢产物稳态水平的改变。发育中的神经系统或许能够代偿由锰暴露引起的神经化学变化。
