The tissues of regions from one half of the brain were
used for ACh assay and those in regions from other half were
selected to determine AChE activity. To avoid the influence of
dominant half of the brain and the differences between ACh
content or AChE activity in right and left halves of brain,
the following procedure was adopted. From 50% of the rats
in each group, the regions from right half of the brain were
selected for ACh assay. The regions of left half were taken
to determine AChE activity; and vice versa from remaining
50% of the rats.