A. Dopamine release from differentiated PC-12 cells under normoxic conditions, in N2, or in xenon. Whereas almost no dopamine was released from control cells during the two-hour period, a strong increase of extracellular dopamine was found when cells were kept in N2. When cells were maintained in a xenon-atmosphere, no dopamine release occurred, there was virtually no difference compared to controls. B. Assessment of cellular damage in PC-12 cells after two-hour incubation. If cells were kept in normal air, or in xenon, only a small amount of LDH was released. Much higher cellular damage was found when cells were incubated in N2. (n = 5; **P < 0.01 with respect to untreated controls).