Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.

<h4>Background</h4>Although visceral pain of gastrointestinal (GI) origin is the major complaint in patients with irritable bowel syndrome (IBS) it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central aro...

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Autores principales:	Anthony C Johnson, Brent Myers, Jelena Lazovic, Rheal Towner, Beverley Greenwood-Van Meerveld
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2010
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/d3e6a4b788084d4aae6b01be7a0dfbf8
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spelling	oai:doaj.org-article:d3e6a4b788084d4aae6b01be7a0dfbf82021-11-25T06:26:57ZBrain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.1932-620310.1371/journal.pone.0008573https://doaj.org/article/d3e6a4b788084d4aae6b01be7a0dfbf82010-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/20052291/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>Although visceral pain of gastrointestinal (GI) origin is the major complaint in patients with irritable bowel syndrome (IBS) it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central arousal circuits including the amygdala. Previously, we found that stereotaxic implantation of corticosterone (CORT) onto the amygdala in rats induced anxiety and colonic hypersensitivity. In the present study we used functional magnetic resonance imaging (fMRI) to identify specific brain sites activated in a rat model characterized by anxiety and colonic hypersensitivity.<h4>Methodology/principal findings</h4>Anesthetized male rats received micropellets (30 microg each) of either CORT or cholesterol (CHOL), to serve as a control, implanted stereotaxically on the dorsal margin of each amygdala. Seven days later, rats were anesthetized and placed in the fMRI magnet (7T). A series of isobaric colorectal balloon distensions (CRD - 90s 'off', 30s 'on', 8 replicates) at two pressures (40 and 60 mmHg) were performed in a standard block-design. Cross correlation statistical analysis was used to determine significant differences between distended and non-distended states in CORT and CHOL-treated animals. Analysis of the imaging data demonstrated greater overall brain activation in response to CRD in rats with CORT implants compared to CHOL controls. Additionally, CORT implants produced significant positive bilateral increases in MRI signal in response to CRD in specific nuclei known as integration sites important in anxiety and pain perception.<h4>Conclusions and significance</h4>These data indicate that chronic exposure of the amygdala to elevated levels of CORT enhances overall brain activation in response to CRD, and identified other specific brain regions activated in response to mechanical distension of the colon. These results demonstrate the feasibility of performing fMRI imaging in a rodent model that supports clinical observations in IBS patients with enhanced amygdala activation and symptomatology of abdominal pain and anxiety.Anthony C JohnsonBrent MyersJelena LazovicRheal TownerBeverley Greenwood-Van MeerveldPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 5, Iss 1, p e8573 (2010)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Anthony C Johnson Brent Myers Jelena Lazovic Rheal Towner Beverley Greenwood-Van Meerveld Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
description	<h4>Background</h4>Although visceral pain of gastrointestinal (GI) origin is the major complaint in patients with irritable bowel syndrome (IBS) it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central arousal circuits including the amygdala. Previously, we found that stereotaxic implantation of corticosterone (CORT) onto the amygdala in rats induced anxiety and colonic hypersensitivity. In the present study we used functional magnetic resonance imaging (fMRI) to identify specific brain sites activated in a rat model characterized by anxiety and colonic hypersensitivity.<h4>Methodology/principal findings</h4>Anesthetized male rats received micropellets (30 microg each) of either CORT or cholesterol (CHOL), to serve as a control, implanted stereotaxically on the dorsal margin of each amygdala. Seven days later, rats were anesthetized and placed in the fMRI magnet (7T). A series of isobaric colorectal balloon distensions (CRD - 90s 'off', 30s 'on', 8 replicates) at two pressures (40 and 60 mmHg) were performed in a standard block-design. Cross correlation statistical analysis was used to determine significant differences between distended and non-distended states in CORT and CHOL-treated animals. Analysis of the imaging data demonstrated greater overall brain activation in response to CRD in rats with CORT implants compared to CHOL controls. Additionally, CORT implants produced significant positive bilateral increases in MRI signal in response to CRD in specific nuclei known as integration sites important in anxiety and pain perception.<h4>Conclusions and significance</h4>These data indicate that chronic exposure of the amygdala to elevated levels of CORT enhances overall brain activation in response to CRD, and identified other specific brain regions activated in response to mechanical distension of the colon. These results demonstrate the feasibility of performing fMRI imaging in a rodent model that supports clinical observations in IBS patients with enhanced amygdala activation and symptomatology of abdominal pain and anxiety.
format	article
author	Anthony C Johnson Brent Myers Jelena Lazovic Rheal Towner Beverley Greenwood-Van Meerveld
author_facet	Anthony C Johnson Brent Myers Jelena Lazovic Rheal Towner Beverley Greenwood-Van Meerveld
author_sort	Anthony C Johnson
title	Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
title_short	Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
title_full	Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
title_fullStr	Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
title_full_unstemmed	Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.
title_sort	brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an fmri study.
publisher	Public Library of Science (PLoS)
publishDate	2010
url	https://doaj.org/article/d3e6a4b788084d4aae6b01be7a0dfbf8
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Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.

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