Autoradiographic studies reveal densities of binding to somatostatin, neurotensin, μ‐opiate, and benzodiazepine receptors in substantia nigra specimens from neurologically normal human brains. Binding to nigral angiotensin converting enzyme is also dense, whereas more modest densities of κ‐opiate, dopamine, and serotonin receptors are noted. In nigral specimens taken from patients with idiopathic Parkinson's disease, substantial reductions in somatostatin, neurotensin, μ‐opiate and κ‐opiate receptors contrast with more modest reductions in dopamine and benzodiazepine I receptor subtypes. Angiotensin converting enzyme, serotonin, and benzodiazepine II binding are virtually unaltered. These results underscore the likelihood of strong peptidergic influences on normal and pathologically altered human nigrostriatal circuitry.
ASJC Scopus subject areas
- Clinical Neurology