中枢前庭系における平衡代償の分子機構

The differential display method was applied to identify genes expression of which is upordown-regulated in the flocculus after unilateral labyrinthectomy (UL) in rats. TotalRNAs from sham operated flocculus and labyrinthectomized flocculus were isolated andamplified by PCR using arbitrary primer sets. PCR products the amounts of which weresignificantly higher or lower in samples from operated animals than those from controls,were cut out of the gel and sequenced. One of the higher expressed fragments showed100% nucleotide sequence identify to protein phosphatase 2A (PP2A) beta catalytic subunitmRNA. In animals with continuous floccular infusion of okadaic acid, a potent inhibitor ofPP 2 A, UL-induced spontaneous nystagmus (SN) lasted significantly longer. One of the lowerexpressed fragments showed 100% nucleotide sequence identify to glutamate receptor (GluR)delta-2 subunit mRNA. UL-induced SN in GluR delta-2 mutant mice was exacerbated at theinitial stage. All these findings suggest that up-regulation of PP2A beta and down regulateGluR delta-2 in flocculus after UL is involved in lesion-induced vestibular plasticity.