| Glutamate immunoreactive terminals in the lateral amygdaloid nucleus: a possible substrate for emotional memory. | |
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MedLine Citation:
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PMID: 1360318 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The ultrastructure and synaptic associations of terminals immunoreactive for L-glutamate (Glu) were examined in the lateral nucleus of the amygdala (AL). All results reported here involved tissue fixed only with paraformaldehyde. The specificity of the antiserum with paraformaldehyde fixation conditions was assessed and confirmed by immuno-dot blot analysis: the reactivity of anti-Glu to glutamic acid was at least 1,000 times greater than the reactivity to other amino acids. At the light microscopic level, Glu-immunoreactive punctate processes and somata were present in AL. At the electron microscopic level, many Glu-immunoreactive terminals were identified. Data analysis was performed on 365 of these labeled terminals. Glu-immunoreactive terminals were 0.3-1.5 microns in diameter and contained numerous small, clear vesicles as well as mitochondria. Many (77%) of the terminals analyzed had morphologically identifiable synaptic specializations. Most (90%) of the Glu-immunoreactive terminals with synaptic specializations formed asymmetric synapses on spines or small dendrites; synaptic specializations on soma or proximal dendrites were rarely seen (< 1%). Glu-immunoreactive terminals were qualitatively compared to terminals in AL labeled with two other antisera: anti-glutaminase, a marker for the enzyme that catalyzes the conversion of glutamine to the releasable or transmitter form of Glu, and anti-gamma-aminobutyric acid (anti-GABA), a marker for the major inhibitory amino acid transmitter in the brain. Terminals immunoreactive for glutaminase, like those immunoreactive for Glu, formed mostly asymmetric synaptic specializations on spines or small dendrites. In contrast, GABA-immunoreactive terminals usually formed symmetric synapses on soma or proximal dendrites and were never observed to form asymmetric axo-spinous contacts. Although Glu is a metabolic precursor to GABA, these data indicate that the majority of Glu-immunoreactive terminals reflect the site of synthesis and release of Glu and not of GABA. In addition, these results provide morphological evidence that Glu plays a role in excitatory neurotransmission at synapses in AL and support the growing body of data implicating excitatory amino acid-mediated synaptic plasticity in-emotional learning and memory processes in AL. |
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Authors:
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C Farb; C Aoki; T Milner; T Kaneko; J LeDoux |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Brain research Volume: 593 ISSN: 0006-8993 ISO Abbreviation: Brain Res. Publication Date: 1992 Oct |
Date Detail:
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Created Date: 1993-01-06 Completed Date: 1993-01-06 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0045503 Medline TA: Brain Res Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 145-58 Citation Subset: IM |
Affiliation:
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Center for Neural Science, New York University, NY 10003. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acids
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analysis* Amygdala / cytology*, physiology, ultrastructure Animals Dendrites / ultrastructure Emotions* Glutamates / analysis*, physiology Glutamic Acid Glutaminase / analysis Immunoblotting Immunohistochemistry Male Memory / physiology* Microscopy, Immunoelectron Neurons / cytology, physiology, ultrastructure Rats Rats, Sprague-Dawley Synapses / ultrastructure gamma-Aminobutyric Acid / analysis |
| Grant Support | |
ID/Acronym/Agency:
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MH38774/MH/NIMH NIH HHS; MH46516/MH/NIMH NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Glutamates; 56-12-2/gamma-Aminobutyric Acid; 56-86-0/Glutamic Acid; EC 3.5.1.2/Glutaminase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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