Changes in calbindin expression within the flocculus after unilateral labyrinthectomy in rats

The role of flocculus in vestibular compensation is still a controversial issue. Calbindin regulates intracellular signaling and has been reported to be a reliable marker of Purkinje cell. Expression of calbindin in flocculus was examined using immunohistochemistry following unilateral labyrinthectomy (UL) in rats. Both the staining intensity and number of calbindin-positive Purkinje cells in the ipsilateral flocculus to the lesion side decreased 6 h after UL compared to the control and contralateral side. Forty-eight hours after UL, the expression of calbindin returned to control levels and asymmetric expression in bilateral flocculus subsided. These transient reduction of calbindin expression in the ipsilateral flocculus may reflect a decrease in the GABAergic inhibition of the floccular Purkinje cell to the ipsilateral vestibular nuclei during vestibular compensation.