Abstract
Monoamine oxidase and aldehyde dehydrogenase activity were significantly reduced in the striatum of rats 8 days after lesion of the nigrostriatal nerve pathway caused by 6-hydroxydopamine. Evidence is presented for the existence of an intraneuronal 'dopamine monoamine oxidase' and intraneuronal aldehyde dehydrogenase. Dopamine concentrations were reduced to 10% of their control values.