Document Detail

Neuromodulator content of hamster intergeniculate leaflet neurons and their projection to the suprachiasmatic nucleus or visual midbrain.
MedLine Citation:
PMID:  11477598     Owner:  NLM     Status:  MEDLINE    
The intergeniculate leaflet (IGL) of the lateral geniculate complex has widespread, bilateral, and reciprocal connections with nuclei in the subcortical visual shell. Its function is poorly understood with respect to its role in visual processing. The most well-known IGL projection, and the only one with a clear function, is the geniculohypothalamic tract (GHT) that terminates in the suprachiasmatic nucleus (SCN), site of the primary circadian clock. The hamster GHT is derived, in part, from IGL neurons containing neuropeptide Y and enkephalin. IGL neurons containing these peptides also project to the pretectal region. The present studies used a combination of immunohistochemical, lesion, and retrograde tracing techniques to study neuron types in the IGL and their projections to hamster SCN and pretectum. Two additional neuromodulators, gamma-aminobutyric acid (GABA) and neurotensin, are shown to be present in IGL neurons. The GABA- and neurotensin-immunoreactive neurons project to the SCN with terminal field patterns very similar to those for neuropeptide Y and enkephalin. IGL neurons of all four types also send projections to the pretectum, but rarely do individual cells project to both the SCN and the pretectum. Nearly all neurotensin is colocalized with neuropeptide Y in IGL neurons, although about half of the neuropeptide Y cells do not contain neurotensin. Otherwise, the extent to which the four neuromodulators are colocalized varies from 6% to 54%. Nearly every SCN neuron appears to contain GABA. In the IGL, the majority of cells studied are not identifiable by GABA immunoreactivity. Putative functions of the various neuromodulator projections from the IGL to pretectum or SCN are discussed.
L P Morin; J H Blanchard
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of comparative neurology     Volume:  437     ISSN:  0021-9967     ISO Abbreviation:  J. Comp. Neurol.     Publication Date:  2001 Aug 
Date Detail:
Created Date:  2001-07-30     Completed Date:  2001-09-13     Revised Date:  2014-09-20    
Medline Journal Info:
Nlm Unique ID:  0406041     Medline TA:  J Comp Neurol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  79-90     Citation Subset:  IM    
Copyright Information:
Copyright 2001 Wiley-Liss, Inc.
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MeSH Terms
Circadian Rhythm
Enkephalins / analysis
Geniculate Bodies / chemistry,  cytology*
Mesocricetus / anatomy & histology*
Neurons / chemistry*,  cytology*
Neuropeptide Y / analysis
Neuropeptides / analysis*
Neurotensin / analysis
Superior Colliculi / chemistry,  cytology
Suprachiasmatic Nucleus / chemistry,  cytology*
Visual Pathways / chemistry,  cytology
gamma-Aminobutyric Acid / analysis
Grant Support
Reg. No./Substance:
0/Enkephalins; 0/Neuropeptide Y; 0/Neuropeptides; 39379-15-2/Neurotensin; 56-12-2/gamma-Aminobutyric Acid

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