6-OHDA denervation substantially decreases DCC mRNA levels in rat substantia nigra compacta

The function of deleted in colorectal cancer (DCC) protein, a member of the immunoglobulin superfamily of cell adhesion molecules, in the adult CNS is unknown. Recently the transcript encoding DCC has been shown to be expressed in a variety of rat brain regions, including the substantia nigra pars compacta and the striatum, which encompasses the nigrostriatal dopaminergic system. In the present study DCC mRNA expression in substantia nigra, striatum, dentate gyrus and piriform cortex was investigated in adult rats using in situ hybridization histochemistry following unilateral injections of 6-hydroxydopamine (6-OHDA) in the median forebrain bundle. DCC mRNA levels were greatly reduced in the substantia nigra ipsilateral to the 6-OHDA lesion compared to those on the contralateral side while there was no apparent effect on DCC mRNA levels in the other regions analysed. These data indicate expression of DCC mRNA in dopamine neurones of the substantia nigra pars compacta and support a role for DCC in the adult CNS, with potential involvement in the function of central dopamine neurones.