Affiliations: [a] Department of Neurology, Medical College of Ohio, Toledo, OH, USA | [b] Department of Otolaryngology, Medical College of Ohio, Toledo, OH, USA
Correspondence:
[*]
Corresponding author: Donald A. Godfrey, Department of Otolaryngology, Medical College of Ohio, 3065 Arlington Ave, Toledo, OH 43614-5907, USA. Tel.: +1 419 383 3571; Fax: +1 419 383 3096; E-mail: [email protected]
Abstract: To determine if synaptic remodeling in the vestibular nuclear complex (VNC) may be involved in vestibular compensation, expressions of growth-associated protein-43 (GAP-43) and synaptosome-associated protein of 25~kDa (SNAP-25) were examined by immunoblotting and immunocytochemistry after unilateral vestibular ganglionectomy (UVG) in rats. GAP-43 expression increased bilaterally in the VNC after UVG, but more rapidly on the lesioned side, and remained high through 60 days. It was mainly associated with boutons at all survival times but was also present in some axonal processes and, at 7 days after UVG, in some somata. SNAP-25 expression also increased bilaterally, more rapidly on the lesioned side, but decreased bilaterally after peaking at 14 days. Its distribution in the VNC resembled that of GAP-43 but was more completely localized to boutons. Comparisons were made with auditory centers of the same rats, since the lesion also deafferented that system. Our results combined with those of previous studies suggest that degeneration of the vestibular nerve fibers is required for increased expression of GAP-43 in the VNC. The results suggest that axonal sprouting and synaptogenesis are involved in synaptic remodeling bilaterally in the rat VNC after UVG.
Keywords: cochlear nucleus, growth associated protein-43, neural plasticity, synaptosome- associated protein of 25 kDa, unilateral vestibular ganglionectomy, vestibular compensation
