Activity-dependent distribution of protein kinase C-δ Within rat cerebellar Purkinje cells following unilateral labyrinthectomy

Protein kinase C isoforms PKC-δand PKC-γ are expressed in Purkinje cells in the uvula-nodulus of the cerebellum. We examined the effect of Purkinje cell activity on the transcription, expression and intracellular distribution of PKC-δand PKC-γ. Relative changes in activity were induced by unilateral labyrinthectomy (UL), decreasing the activity of Purkinje cells on the side of the labyrinthectomy relative to the contralateral side with intact vestibular input. After a UL, there was decreased immunolabeling of Purkinje cell axon terminals in the ipsilateral caudal vestibular complex by antisera to PKC-δ, but not PKC-γ. Western blots prepared from the uvula-nodulus and caudal vestibular complex showed an increase in the cytosolic PKC-δand a decrease in membrane-associated PKC-δin the ipsilateral uvula-nodulus 12-48 h after the UL. Hybridization histochemistry and semiquantitative reverse transcription polymerase chain reaction (RT-PCR) demonstrated no change in transcription of PKC-δ mRNA in the uvula-nodulus 1-240 h after unilateral labyrinthectomy. We conclude that both PKC-δ and PKC-γ are constitutively expressed in Purkinje cells. The targeting of PKC-δ, but not PKC-γ, to Purkinje neuron synaptic terminals is influenced by activity.