Dendritic growth and spine formation in response to XXXX in the developing Purkinje cell.

@entity172 @entity440 @entity1420 @entity53 @entity12209 @entity35 @entity165
Neurosteroids are synthesized de novo in the brain, and the cerebellar Purkinje cell is a major site for neurosteroid formation. We have demonstrated that the Purkinje cell possesses intranuclear receptor for @entity1420 and actively produces @entity1420 de novo from @entity165 only during @entity35 neonatal life, when cerebellar cortical formation occurs dramatically. We have further demonstrated that @entity1420 promotes dendritic growth, spinogenesis, and synaptogenesis via its receptor in this neuron in the neonate. On the other hand, @entity172 may also play an important role in the process of cerebellar cortical formation, because the neonatal @entity35 Purkinje cell possesses @entity172 receptor ( @entity12209 . However, @entity172 formation in the neonatal cerebellum is still unclear. In this study, we therefore analyzed the biosynthesis and action of @entity172 in Purkinje cells during neonatal life. RT-PCR-Southern and in situ hybridization analyses showed that Purkinje cells expressed the key enzyme of @entity172 formation, cytochrome P450 aromatase, in neonatal @entity35 . A specific enzyme immunoassay for @entity53 further indicated that cerebellar @entity53 concentrations in the neonate were significantly higher than those in the prepuberty and adult. Both in vitro and in vivo studies with newborn @entity35 showed that @entity53 promoted dose-dependent dendritic growth of Purkinje cells. @entity53 also increased the density of Purkinje dendritic spines. These effects were inhibited by the ER antagonist @entity440 . These results suggest that @entity53 in the developing Purkinje cell promotes dendritic growth and spinogenesis via @entity12209 in this neuron. @entity53 as well as @entity1420 may contribute to the growth of Purkinje cells during the cerebellar cortical formation.
