Substance P immunoreactivity in the post-mortem parkinsonian brain.

The amount of substance P immunoreactivity (SPI) was measured by radioimmunoassay from the cerebral cortex, caudate nucleus, putamen, pallidum, substantia nigra, hypothalamus, nucleus accumbens, amygdala and hippocampus from autopsy brains. The whole material consisted of 42 parkinsonian patients and 31 controls. The amount of SPI was significantly decreased in the substantia nigra of the parkinsonian brain. There was also a significant decrease of SPI in the putamen of those parkinsonian patients, who had not received levoDOPA treatment. The levels of SPI in the other brain regions studied did not show any difference between parkinsonian patients and controls. The results obtained suggest that substance P (SP) may have a role in the pathophysiology of Parkinson's disease.