Document Detail


Amino acid neurotransmitter release and learning: a study of visual imprinting.
MedLine Citation:
PMID:  15207342     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The intermediate and medial part of the hyperstriatum ventrale (IMHV) is an area of the domestic chick forebrain that stores information acquired through the learning process of imprinting. The effects of visual imprinting on the release of the amino acids aspartate, arginine, citrulline, gamma-aminobutyric acid (GABA), glutamate, glycine and taurine from the left and right IMHVs in vitro were measured at 3.5, 10 and 24 h after training. Chicks were exposed to an imprinting stimulus for 1 h, their preferences measured 10 min afterward and a preference score calculated as a measure of the strength of learning. Potassium stimulation was used to evoke amino acid release from the IMHVs of trained and untrained chicks in the presence and absence of extracellular Ca2+. Ca2+-dependent, K+-evoked release of glutamate was significantly (34.4%) higher in trained than in untrained chicks. This effect was not influenced by time after training or by side (left or right IMHV). Training influenced the evoked release of GABA and taurine from the left IMHV at both 3.5 and 10 h. The training effects at the two times were statistically homogeneous so data (< or = 10 h group) were combined for each amino acid respectively. For this < or = 10 h group, evoked release increased significantly with preference score. In contrast, for the 24 h group, evoked release of GABA and taurine was not significantly correlated with preference score. There were no significant correlations between preference score and GABA or taurine release in the right IMHV at any time, nor in the absence of extracellular calcium. No significant effects of training condition, time or side were observed for any other amino acid in the study. The present findings suggest that soon after chicks have been exposed to an imprinting stimulus glutamatergic excitatory transmission in IMHV is enhanced, and remains enhanced for at least 24 h. In contrast, the learning-related elevations in taurine and GABA release are not sustained over this period. The change in GABA release may reflect a transient increase in inhibitory transmission in the left IMHV.
Authors:
R M Meredith; B J McCabe; K M Kendrick; G Horn
Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neuroscience     Volume:  126     ISSN:  0306-4522     ISO Abbreviation:  Neuroscience     Publication Date:  2004  
Date Detail:
Created Date:  2004-06-21     Completed Date:  2004-08-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7605074     Medline TA:  Neuroscience     Country:  United States    
Other Details:
Languages:  eng     Pagination:  249-56     Citation Subset:  IM    
Copyright Information:
Copyright 2004 IBRO
Affiliation:
Sub-Department of Animal Behaviour, Department of Zoology, University of Cambridge, Madingley, Cambridge CB3 8AA, UK. rhiannon.meredith@physiol.ox.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / metabolism,  secretion*
Animals
Basal Ganglia / metabolism,  secretion
Chickens
Imprinting (Psychology) / physiology*
Learning / physiology
Photic Stimulation / methods*
Physical Conditioning, Animal
Time Factors
Chemical
Reg. No./Substance:
0/Amino Acids

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