Differential damage by hypoxia to dopamine and serotonin nerve terminals.

Serotonin and dopamine resemble each other in terms of their synthetic and degradative pathways, as well as in terms of structural features. However, responses to a low-oxygen environment differ between these two compounds. In this experiment, we studied the fluctuations of levels of serotonin, dopamine and their metabolites in the striatum of the rat brain under low-oxygen conditions using a microdialysis technique. Comparison of the extents of increases in extracellular levels of dopamine and serotonin, accompanied by decreases in levels of metabolites, indicates that the effects of hypoxia on the two types of neuronal terminal are different. This study suggests that dopamine plays a more important role than serotonin in the mechanism of irreversible destruction of neurons during moderate hypoxia.