Developmental distribution of calretinin in mouse barrel cortex.

We describe the postnatal development of calretinin expression in the mouse barrel cortex by immunohistochemistry. A densely staining neuropil and numerous cell bodies appeared throughout layer V, but only within barrel septa of layer IV, at postnatal day 4. This staining pattern became most robust at postnatal day 8. Thereafter, calretinin expression became reduced until the third postnatal week when it attained its mature levels, and the barrel-specific staining was no longer apparent.