Substance P in the human brain.

The distribution of substance P immunoreactive sites was investigated by immunoenzymatic methods in a large series of paraffin embedded human brain sections from the collection assembled by Oscar and Cécile Vogt several decades ago, as well as from more recent post-mortem material. These studies demonstrated that substance P immunoreactivity was preserved in archival material permitting a detailed account of the localization of immunoreactive cell bodies, fibre networks and tracts in the human brain. Previous observations made on experimental animals and man were confirmed and extended. Additionally, substance P immunoreactive cell bodies were seen in most cortical areas and novel features were noted in the distribution of substance P-containing elements in the tuberal region, corpus striatum, substantia nigra (particularly in relationship to blood vessels) and in association with melanin-containing cells. Reconstruction of some substance P pathways was attempted by the analysis of semi-serial sections in more than one plane. Immunocytochemistry, in combination with image analysis, enabled some measurements of the differential concentrations of substance P immunoreactive material to be made and allowed a close correlation of this with defined anatomical landmarks or enkephalin immunoreactive sites.