The Role of Gastrin-releasing Peptide in Photic Entrainment

The Role of Gastrin-releasing Peptide in Photic Entrainment

Bibliographic Details
Main Author: Kallingal, George J.
Language:English
Published: Kent State University / OhioLINK 2008
Subjects:
Biomedical Research
suprachiasmatic
gastrin-releasing peptide
glutamate
serotonin
NPY
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=kent1208972062
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-kent12089720622021-08-03T05:36:32Z The Role of Gastrin-releasing Peptide in Photic Entrainment Kallingal, George J. Biomedical Research suprachiasmatic gastrin-releasing peptide glutamate serotonin NPY <p>Physiological and behavioral rhythms are generated by the suprachiasmatic nucleus (SCN). The SCN can be roughly divided into two regions, the core and the shell. Within the core and the shell, various cellular markers and neuropeptides integrate afferent photic and non-photic signals that are essential to synchronize clock function. In Syrian hamsters (Mesocricetus auratus), gastrin releasing peptide (GRP) appears to be an important relay signal between these two SCN regions. GRP also serves as an output signal in other brain regions including the supraoptic nucleus (SON). In this dissertation, the role of GRP in the SCN will be examined in the context of regulating both afferent and efferent signals to and from the SCN in an effort to synchronize the clock. </p><p>Administration of GRP to the SCN induces phase shifts in a manner similar to light. The behavioral experiments described seek to explore the effects of glutamate, serotonin, and neuropeptide Y (NPY) on GRP-induced phase shifts. AP5, an NMDA receptor antagonist, can attenuate GRP-induced phase shifts in the early subjective night and can additionally block the effects of light, but not GRP, when administered after the phase shifting stimulus. Furthermore, serotonin and NPY, carriers of non-photic signals, can oppose the action of GRP in the SCN. These results suggest that GRP signaling in the SCN is dependent on the regulation provided by glutamatergic, serotonergic, and NPYergic stimulation. </p><p>GRP administered to the SCN additionally affects the cellular response of cells in the SON. GRP action in this SCN output appears not to be regulated by glutamate or serotonin. Administration of GRP to the SON additionally alters the cellular response of SCN cells and microinjection of GRP or bicuculline, a GABAA receptor antagonist, to the SON region can elicit phase shifts. These data suggest that the SCN and SON have reciprocal neuronal projections that may mediate photic entrainment through action of GRP. These experiments greatly increase our knowledge of the role of GRP in circadian rhythms by examining the interaction of other neurotransmitter systems on GRP signaling. These experiments additionally implicate the SON as a potential mediator of photic entrainment.</p> 2008-04-23 English text Kent State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=kent1208972062 http://rave.ohiolink.edu/etdc/view?acc_num=kent1208972062 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Biomedical Research
suprachiasmatic
gastrin-releasing peptide
glutamate
serotonin
NPY
spellingShingle Biomedical Research
suprachiasmatic
gastrin-releasing peptide
glutamate
serotonin
NPY
Kallingal, George J.
The Role of Gastrin-releasing Peptide in Photic Entrainment
author Kallingal, George J.
author_facet Kallingal, George J.
author_sort Kallingal, George J.
title The Role of Gastrin-releasing Peptide in Photic Entrainment
title_short The Role of Gastrin-releasing Peptide in Photic Entrainment
title_full The Role of Gastrin-releasing Peptide in Photic Entrainment
title_fullStr The Role of Gastrin-releasing Peptide in Photic Entrainment
title_full_unstemmed The Role of Gastrin-releasing Peptide in Photic Entrainment
title_sort role of gastrin-releasing peptide in photic entrainment
publisher Kent State University / OhioLINK
publishDate 2008
url http://rave.ohiolink.edu/etdc/view?acc_num=kent1208972062
work_keys_str_mv AT kallingalgeorgej theroleofgastrinreleasingpeptideinphoticentrainment
AT kallingalgeorgej roleofgastrinreleasingpeptideinphoticentrainment
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