Transneuronal down regulation of vestibulo-ocular neurons following vestibular ablation.
Unilateral ablation of vestibular input causes lasting morphological changes bilaterally in superior vestibulo-ocular neurons (SVON). The present study was performed to see if these changes in SVON are more pronounced after bilateral vestibular neurectomy. Twenty-three SVON from both vestibular nuclei of 2 cats sacrificed 8 weeks after bilateral ablation were examined utilizing morphometric ultrastructural techniques. There was a significantly greater somal atrophy, loss of synaptic profiles, rough endoplasmic reticulum and polyribosomes compared to unilateral neurectomy. These changes indicate a down regulation that is proportional to the level of deafferentation and may account for functional deficits seen in the vestibulo-ocular reflex after peripheral ablation.
Gacek
R R
RR
Department of Otolaryngology and Communication Sciences, Syracuse, New York, USA.
Schoonmaker
J E
JE
D000818:Animals; D002415:Cats; D015536:Down-Regulation; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D014725:Vestibular Nerve / Q000166:cytology* / Q000502:physiology / Q000601:surgery; D014726:Vestibular Nuclei / Q000166:cytology* / Q000502:physiology / Q000601:surgery