Quantitative inter-strain comparison of the distribution of choline acetyltransferase activity in the rat cochlear...

The distribution of choline acetyltransferase activity in the cochlear nucleus of Sprague-Dawley albino rats was quantitatively compared to those in two strains of pigmented rats, Long Evans hooded and Brown Norway, using microdissection and radiometric assay techniques. Although activities tended to be, on the whole, higher in the albino rats, the differences were fairly minor. The relative distributions of choline acetyltransferase activity were generally similar among the 3 rat strains, not only among regions, but also within regions. Stain for acetylcholinesterase activity in the cochlear nucleus also had a similar appearance among the 3 rat strains. These chemical results are consistent with previous anatomical and physiological studies suggesting that auditory differences between albino and pigmented animals may not be as great in the cochlear nucleus as in the superior olivary complex.