A possible role of transient AChE expression in the medial geniculate of developing rats

Acetylcholinesterase (AChE) and calbindin D-28K (CaBP) are transiently expressed in the rat auditory nuclei during the early postnatal period. In the ventral division of the medial geniculate body (MGV), the transient AChE expression in the neuropil is replaced by CaBP expression in the neurones. The time correlation between the up- and down-regulations in these neuro-chemicals suggests some switching over mechanism. A lesion of the inferior colliculus (IC) decreases the AChE reactivity in terminal field of the IC-MGV projections. We here demonstrate that the IC lesion results in CaBP expressions in neurones of the MGV before its normal onset. It is thus possible that the transiently expressed AChE plays an important role in the intercellular signal transduction for neurochemical phenotype expressions.