Effect of decreased oxygen on in vitro release of endogenous 3,4-dihydroxyphenylethylamine from mouse striatum.

The effects of hypoxia on release of endogenous 3,4-dihydroxyphenylethylamine (DA, dopamine) were investigated in mouse striatal slices. Following a 60-min preincubation, potassium increased DA release 12 times between zero and 1 min. By 10 min, uptake processes exceeded release and DA levels in the media decreased. Hypoxia (low oxygen) and anoxia (no oxygen) increased DA in the media by 120 and 205%, respectively, but did not alter dihydroxyphenylacetic acid concentrations. Under similar conditions, anoxia increased [3H]DA uptake eight-fold. For the uptake studies, the amount of DA added to the media was critical; in the presence of high concentrations of DA, anoxia reduced reuptake. Regardless of exogenous DA, hypoxia and anoxia increased extracellular DA, which may play a role in ischemic cell damage.