Journal of Veterinary Medical Science
Online ISSN : 1347-7439
Print ISSN : 0916-7250
ISSN-L : 0916-7250
Pharmacology
MicroPET Detection of Regional Brain Activation Induced by Colonic Distention in a Rat Model of Visceral Hypersensitivity
Katsuyo OHASHIKatsuomi ICHIKAWALaigao CHENMichael CALLAHANKenneth ZASADNYYoichi KUREBAYASHI
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JOURNAL FREE ACCESS

2008 Volume 70 Issue 1 Pages 43-49

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Abstract

Using microPET and 18F-fluorodeoxyglucose (18F-FDG) as a tracer, we investigated regional brain activation in a rat model of visceral hypersensitivity induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS injection into the proximal colon through laparotomy resulted in a significant, sustained decrease in the pain threshold to mechanical distention of the distal colon, indicating a phenomenon referred to as visceral hypersensitivity. When TNBS-induced colonic hypersensitivity was fully developed, all the TNBS-treated rats presented characteristic pain behaviors in response to colonic distention at previously innocuous pressure (0-35 mmHg) that produced no abdominal pain in sham-operated control animals. In microPET study, colonic distention at the normally non-painful pressure produced significant increases in 18F-FDG uptake in the thalamus and sensory cortex I of TNBS-treated rats. Since the increases in 18F-FDG uptake in the brain regions were completely abolished by an analgesic dose of morphine (375 μg/kg, s.c.), it is most likely that the regional brain activation detected by microPET is a pain-related central event. The pharmacological and microPET data indicate that colonic distention at the normally non-painful pressure activates specific brain regions in rats with TNBS-induced visceral hypersensitivity, and the microPET protocol described here could provide an objective measure to test visceral analgesic compounds.

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© 2008 by the Japanese Society of Veterinary Science

この記事はクリエイティブ・コモンズ [表示 - 非営利 - 改変禁止 4.0 国際]ライセンスの下に提供されています。
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
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