Mm. Goto et al., TRANSIENT CHANGES IN FLOCCULONODULAR LOBE PROTEIN-KINASE-C EXPRESSIONDURING VESTIBULAR COMPENSATION, The Journal of neuroscience, 17(11), 1997, pp. 4367-4381
Protein kinase C (PKC) is a family of intracellular signal transductio
n enzymes, comprising isoforms that vary in sensitivity to calcium, ar
achidonic acid, and diacylglycerol. PKC isoforms alpha, gamma, and del
ta are expressed by cerebellar Purkinje cells and neurons in the cereb
ellar nuclei and vestibular nuclei of the Long-Evans rat. In control r
ats, these PKCs are distributed symmetrically in the flocculonodular-l
obe Purkinje cells. Behavioral recovery from vestibular dysfunction pr
oduced by unilateral labyrinthectomy (UL) is accompanied by asymmetric
expression of PKC isoforms in these regions within 6 hr after UL. The
se expression changes were localized within parasagittal regions of th
e floculus and nodulus. The distribution of PKC alpha, -gamma, and -de
lta were identical, suggesting that they are coregulated in cerebellar
Purkinje cells during this early compensatory period. The pattern of
Purkinje cell PKC expression returned to the control, symmetric distri
bution within 24 hr after UL. It is hypothesized that these regional c
hanges in Purkinje cell PKC expression are an early intracellular sign
al contributing to vestibular compensation. In particular, regulation
of PKC expression may contribute to changes in the efficacy of cerebel
lar synaptic plasticity during the acute post-UL period.