SHORT-TERM AND LONG-TERM EFFECTS OF POSTNATAL HYPOXIA ON THE STRIATAL METABOLISM AND TRANSPORT OF DOPAMINE

The striatal concentrations of dopamine (DA) and its metabolites DOPAC, HVA and 3-MT, the tyrosine hydroxylase (TH) activity and the DA uptake were determined in infant and adult rats after the exposure to hypobaric hypoxia (pO2 11kPa). After 1 hour of single hypoxia at the 11th day of life HVA was elevated whereas after 5 or 10 hours DA and all metabolites were reduced. Following repetitive hypoxia (10 hours daily) from the 2nd till the 11th day catecholamine concentrations were unchanged. DA uptake rates at the 11th day of life were reduced after single hypoxia but not altered after the repetitive one. TH activity was increased in hypoxic rats al the 7th day of life but in the control range beyond. Following one hour of single hypoxia in adulthood, HVA and 3-MT were reduced and DA increased in rats treated with repetitive postnatal hypoxia whereas only HVA was decreased in postnatal controls. After 16 hours of single hypoxia in adulthood, 3-MT was diminished only in postnatal controls. These results demonstrate a different response to hypoxia of infant and adult animals and long-term effects of repetitive postnatal hypoxia on the striatal DA system.