6-Hydroxydopamine: evidence for superoxide radical as an oxidative intermediate.

Superoxide dismutase inhibited the autoxidation of 6-hydroxydopamine as measured by the rate of formation of a quinone and the rate of oxygen consumption. These observations demonstrate the formation of the superoxide radical during the autoxidation process. This finding may be relevant to the mechanism of adrenergic nerve terminal degeneration caused by 6-hydroxydopamine.