title: Episodic vestibular disruption following ablation of the inferior olive in rats: behavioral correlates.
abstract: The experiments herein investigate whether the behavioral responses to transient and episodic vestibular disruption and permanent ablation are distinct in the absence of climbing fiber input. Subjects in group 1 received an IP injection of PBS followed by an IP injection of niacinamide. Seven days later these rats received the first of 3 serial transtympanic injections of TTX on the same side with 7 days between each injection. Following each TTX injection rats displayed unilateral vestibular symptoms that persisted beyond 48h. Spontaneous barrel rolling behavior was not observed. Group 2 subjects received an IP injection of 3-acetylpyridine (3-AP)+niacinamide followed by the same TTX regimen as group 1. Following each TTX injection vestibular symptoms (severe body twisting and persistent spontaneous barrel rolling) emerged rapidly (<15min) and resolved by 72h. Group 3 subjects received an IP injection of 3-AP+niacinamide and 7 days later a single unilateral transtympanic injection of sodium arsanilate. Rats in group 3 developed vestibular symptoms similar to those observed in group 2 although there was no resolution of these symptoms. The results indicate that TTX has a rapid rate of infiltration and blockade of the VIIIth nerve that persists for >48h and then completely resolves. The contrast in vestibular symptoms between groups 1 and 2 suggest that climbing fibers are recruited soon after onset of vestibular disruption and play a role in attenuating the severity of vestibular symptoms associated with transient/episodic vestibular disruption.
authors.affiliation: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Evansville Center for Medical Education, 8600 University Blvd., Evansville, IN 47712, United States. dsaxon@IUPUI.edu
authors.forename: Dale W
authors.initials: DW
authors.lastname: Saxon
authors.forename: Gary
authors.initials: G
authors.lastname: White
mesh_terms: D000818:Animals; D001340:Autonomic Nerve Block / Q000379:methods; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D004333:Drug Administration Routes; D004334:Drug Administration Schedule; D004347:Drug Interactions; D008297:Male; D009498:Neurotoxins / Q000008:administration & dosage; D009536:Niacinamide / Q000008:administration & dosage; D009847:Olivary Nucleus / Q000473:pathology / Q000502:physiology*; D011042:Poisons / Q000008:administration & dosage; D011725:Pyridines / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012027:Reflex, Vestibulo-Ocular / Q000187:drug effects / Q000502:physiology*; D016622:Silver Staining / Q000379:methods; D013779:Tetrodotoxin / Q000008:administration & dosage; D015837:Vestibular Diseases / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D000159:Vestibulocochlear Nerve / Q000187:drug effects / Q000502:physiology
chemical_list: D009498:Neurotoxins; D011042:Poisons; D011725:Pyridines; C010835:3-acetylpyridine; D009536:Niacinamide; D013779:Tetrodotoxin