Document Detail


The importance of N-methyl-D-aspartate (NMDA) receptors in subtraction of electrosensory reafference in the dorsal nucleus of skates.
MedLine Citation:
PMID:  20639432     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The dorsal nucleus of the little skate is a cerebellum-like sensory structure that adaptively filters out predictable electrosensory inputs. The filter's plasticity is mediated by anti-Hebbian associative depression at the synapses between parallel fibers and ascending efferent neurons (AENs). Changes in synaptic strength are indicated by the formation of a cancellation signal which is initiated by co-activation of parallel fibers and AENs, and can be reversed by parallel fiber activity in the absence of AEN activation. In other cerebellum-like sensory structures, the formation of the cancellation signal requires activation of postsynaptic NMDA receptors on the principal neurons. We demonstrate here by immunohistochemistry that the somas and the initial portion of both apical and basal dendrites of the AENs are labeled with antibodies raised against the NR1 subunit of NMDA receptors from a South American electric fish. In in vivo physiological experiments, we show that the formation of the cancellation signal induced by coupling an electrosensory stimulus to ventilatory movements or direct parallel fiber stimulation is blocked when either of the NMDA receptor antagonists 2-amino-5-phosphonovaleric acid (APV) or MK801 is injected into the molecular layer above the recorded AEN. Blocking NMDA receptors prevented formation of a cancellation signal in 79% (15/19; APV) and 60% (3/5; MK801) of the AENs. This blockage was reversible in 40% (6/15) of the AENs after APV removal. Thus, in the dorsal nucleus, the activity-dependent, long-lasting but reversible change in synaptic strength of the parallel fiber-AEN synapses appears to be an NMDA receptor-dependent process.
Authors:
Zhi Zhang; David Bodznick
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  213     ISSN:  1477-9145     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-19     Completed Date:  2010-10-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  2700-9     Citation Subset:  IM    
Affiliation:
Biology Department, Wesleyan University, Middletown, CT 06459, USA. zzhang@wesleyan.edu
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MeSH Terms
Descriptor/Qualifier:
2-Amino-5-phosphonovalerate / pharmacology
Animals
Antibody Specificity / immunology
Dizocilpine Maleate / pharmacology
Mass Spectrometry
Microscopy, Confocal
Neurons, Afferent / drug effects,  metabolism*
Neurons, Efferent / drug effects,  metabolism
Protein Subunits / metabolism
Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors,  metabolism*
Signal Transduction / drug effects
Skates (Fish) / metabolism*
Software
Thalamic Nuclei / drug effects*,  metabolism*
Chemical
Reg. No./Substance:
0/Protein Subunits; 0/Receptors, N-Methyl-D-Aspartate; 76726-92-6/2-Amino-5-phosphonovalerate; 77086-22-7/Dizocilpine Maleate

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


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