Quantitative imaging of substance P in the human brain using a brain mapping analyzer

Area of Science:

• Neuroscience
• Neuroanatomy
• Neurochemistry

Background:

• Substance P (SP) is a neuropeptide involved in various neurological functions.
• Understanding SP distribution is crucial for comprehending brain function, especially in aging.

Purpose of the Study:

• To quantitatively analyze the distribution of SP-like immunoreactive neurons in the brains of aged normal humans.
• To map SP distribution in the striatum and substantia nigra.

Main Methods:

• Immunohistochemical staining for SP in coronal brain sections.
• Quantitative analysis using a human brain mapping analyzer (microphotometry).
• Measurement of fluorescence intensity across millions of microareas per section.

Main Results:

• Conspicuously intense SP-like immunoreactivity was found in the substantia nigra and globus pallidus.
• SP intensity in the substantia nigra pars compacta was 25% higher than in the pars reticulata.
• SP intensity in the globus pallidus internal segment was double that of the external segment, with highest concentration medially.

Conclusions:

• SP distribution in aged human brains is characterized by high concentrations in specific basal ganglia structures.
• Melanin-containing neurons in the substantia nigra correlate with SP distribution.
• Moderate and patchy SP distribution was observed in the caudate nucleus and putamen.