CCK-8-immunoreactivity distribution in human brain: selective decrease in the substantia nigra from parkinsonian patients

The regional distribution of immunoassayable CCK-8 was determined in 12 regions of control and parkinsonian human brain, with specific attention to the possible regional coexistence of CCK-8 with dopamine. In Parkinson's disease, CCK-8-I levels were only decreased in the substantia nigra where dopamine cell bodies lie, and not in striatal and corticolimbic dopamine projecting areas. Our results suggest that the major proportion of dopaminergic neurones degenerated in Parkinson's disease may not contain the CCK-8 peptide.