Document Detail


Glycine receptor deficiency and its effect on the horizontal vestibulo-ocular reflex: a study on the SPD1J mouse.
MedLine Citation:
PMID:  23296843     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Inhibition is critical in the pathways controlling the vestibulo-ocular reflex (VOR) and plays a central role in the precision, accuracy and speed of this important vestibular-mediated compensatory eye movement. While γ-aminobutyric acid is the common fast inhibitory neurotransmitter in most of the VOR microcircuits, glycine is also found in key elements. For example, the omnidirectional pause neurons (OPNs) and inhibitory burst neurons in the horizontal VOR both use glycine as their preferred inhibitory neurotransmitter. Determining the precise contribution of glycine to the VOR pathway has been difficult due to the lack of selective tools; however, we used spasmodic mice that have a naturally occurring defect in the glycine receptor (GlyR) that reduces glycinergic transmission. Using this animal model, we compared the horizontal VOR in affected animals with unaffected controls. Our data showed that initial latency and initial peak velocity as well as slow-phase eye movements were unaffected by reduced glycinergic transmission. Importantly however, there were significant effects on quick-phase activity, substantially reducing their number (30-70 %), amplitude (~55 %) and peak velocity (~38 %). We suggest that the OPNs were primarily responsible for the reduced quick-phase properties, since they are part of an unmodifiable, or more 'hard-wired', microcircuit. In contrast, the effects of reduced glycinergic transmission on slow-phases were likely ameliorated by the intrinsically modifiable nature of this pathway. Our results also suggested there is a 'threshold' in GlyR-affected animals, below which the effects of reduced glycinergic transmission were undetected.
Authors:
Patrick P Hübner; Rebecca Lim; Alan M Brichta; Americo A Migliaccio
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2013-01-08
Journal Detail:
Title:  Journal of the Association for Research in Otolaryngology : JARO     Volume:  14     ISSN:  1438-7573     ISO Abbreviation:  J. Assoc. Res. Otolaryngol.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-03-12     Completed Date:  2013-09-06     Revised Date:  2014-04-01    
Medline Journal Info:
Nlm Unique ID:  100892857     Medline TA:  J Assoc Res Otolaryngol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  249-59     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Disease Models, Animal
Down-Regulation / physiology
Eye Movements / genetics*,  physiology*
Female
Glycine / physiology
Heterozygote
Homozygote
Male
Mice
Mice, Mutant Strains
Receptors, Glycine / deficiency*,  genetics,  physiology
Reflex, Vestibulo-Ocular / physiology*
Signal Transduction / physiology*
Time Factors
gamma-Aminobutyric Acid / physiology
Chemical
Reg. No./Substance:
0/Receptors, Glycine; 56-12-2/gamma-Aminobutyric Acid; TE7660XO1C/Glycine
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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