Ontogenic changes in expression of neuron-specific enolase (NSE) and its mRNA in the Purkinje cells of the rat cerebellum: immunohistochemical and in situ hybridization study.

In the postnatal development of rats, neuron-specific enolase (NSE)-immunoreactivity first appeared in the Purkinje cells at postnatal day 3 (P3) and elevated strikingly at P9 when almost all the Purkinje cell somata and dendrites exhibited the intense immunoreactivity. In situ hybridization signals for NSE-mRNA also increased markedly in the Purkinje cell somata from P3 to P9. These results indicate that the NSE synthesis is transiently enhanced in the Purkinje cells from P3 to P9 at the transcriptional level. At P11 and thereafter NSE-immunoreactive Purkinje cells decreased in number, and no significant immunoreaction was detected in their somata and dendrites in the adulthood, whereas distinct immunoreactivity for NSE was still detected in the Purkinje cell axons until the adult stage. However, the signals for NSE-mRNA were still localized in the Purkinje cell somata after P11 until the adult. The possible involvement of the negative translational control and/or the axoplasmic transport of NSE was briefly discussed to explain this discrepancy between NSE-immunoreactivity and its mRNA expression in the Purkinje cells in the late postnatal development.