Quantitative histochemistry of acetylcholinesterase in rat and human brain postmortem.

A quantitative analysis of acetylcholinesterase (AChE) activity in histochemically stained sections of rat and human brain can be achieved through the use of internal standards and computerized image analysis. Tissue standards containing known amounts of a highly purified AChE preparation are sectioned and incubated under the same conditions as experimental sections. A computerized image analyzer is used to convert the optical density of the stain to units of enzyme content via the standard curve. The method generates reliable and reproducible quantitative values from very small brain regions and nuclei, combining the quantitative character of a radiometric assay with the superior anatomical resolution of histochemistry.