Differences in NOS protein expression and activity in the rat vestibular nucleus following unilateral labyrinthectomy.

We used Western blotting to analyse the expression of different isoforms of nitric oxide synthase (NOS) in the rat vestibular nucleus complex (VNC) at various times following unilateral vestibular deafferentation (UVD), together with a radioenzymatic assay to compare NOS activity at the same time points. nNOS expression did not change significantly in the ipsilateral or contralateral VNC at any time following UVD. However, eNOS expression decreased significantly (P<0.05) in the contralateral VNC at 6 h post-UVD, recovering to normal levels by 50 h. iNOS was not expressed at any time following UVD. NOS activity demonstrated a significant increase in the contralateral VNC at 6 h post-UVD (P<0.05), recovering toward normal levels by 50 h.