DEVELOPMENT OF MONOAMINE SYSTEMS AFTER NEONATAL ANOXIA IN RATS

Neurochemical and morphological effects of neonatal anoxia on monoamin e systems were studied after 100% N2 exposure for 25 min at 30 h postn atally (postnatal day 2-P2). At 20 min after anoxia, reductions of tis sue levels of cerebellar noradrenaline (NA) and striatal dopamine (DA) and metabolites were seen, while 5-hydroxyindoleacetic acid (5-HIAA) was increased in cortex and cerebellum. At P7, NA increased in cerebel lum, while serotonin (5-HT) and 5-HIAA decreased in cortex and cerebel lum. At P21, increased hippocampal NA and striatal homovanillic acid ( HVA) were found, while striatal 5-HT decreased and 5-HIAA increased in striatum and hippocampus. At P60, striatal 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-HIAA levels were found to be enhanced. No effects w ere seen on 5-HT, tyrosine hydroxylase, or DARPP-32 immunostaining in cortex, hippocampus, and striatum. Thus, the neonatal anoxia induced b oth acute and persistent neurochemical abnormalities in monoamine syst ems that were not accompanied by morphological changes detectable with the methods used. The monoamine alterations found could be critically connected to the behavioral disturbances observed in rats after neona tal anoxia. The findings may also be of relevance to dysfunctions seen in humans after perinatal oxygen deficiency, e.g., the attention defi cit hyperactivity disorder syndrome.