Two populations of calbindin D28k-immunoreactive neurones in the striatum of the rat.

In order to examine the localisation of calbindin D28k in the normal striatum of the rat, immunocytochemistry using monoclonal antibodies was carried out at both the light and electron microscopic levels. As has previously been shown, many striatal spiny neurones were immunopositive, however, a small population of neurones with smooth dendrites and indented nuclei were also identified. At least some of these cells also displayed NADPH-diaphorase activity. These findings indicate that, in common with the primate striatum and grafted striatal tissue in the rat, the normal rat striatum contains at least two populations of neurones that express calbindin D28k.