Masayuki Uchida1, Orie Kobayashi1, Miku Yoshida2, Machiko Miwa2, Reina Miura2, Hiroko Saito2, Yukinori Nagakura3,4,5. 1. Food Science and Technology Research Laboratories, R&D Division, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan. 2. Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kohbata, Aomori-city, Aomori, 030-0943, Japan. 3. Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kohbata, Aomori-city, Aomori, 030-0943, Japan. nagakurayu@iuhw.ac.jp. 4. Center for Brain and Health Sciences, Aomori University, 109-1 Takama, Ishie, Aomori-city, Aomori, 038-0003, Japan. nagakurayu@iuhw.ac.jp. 5. Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara-city, Tochigi, 324-8501, Japan. nagakurayu@iuhw.ac.jp.
Abstract
BACKGROUND: Fibromyalgia (FM) is a disorder characterized by widespread chronic pain as core symptom and a broad range of comorbidities. Despite the prevalence of gastrointestinal (GI) comorbidities in patients with FM, GI functions have rarely been investigated in animal models of FM. AIMS: The purpose of the present study is to investigate the coexistence of alterations of GI function in the reserpine-induced myalgia (RIM) rat, a validated FM model associated with disruption of monoamine system. METHODS: Paw withdrawal threshold (von Frey hair test) was assessed as pain-associated indicator. Gastric emptying (13C breath test), small intestinal transit (charcoal meal test), and fecal water content were investigated as GI functions. RESULTS: The specific regimen of reserpine for the RIM rat, i.e., 1 mg/kg s.c., once daily for three consecutive days, caused a reduction of paw withdrawal threshold (i.e., mechanical allodynia) on days 3, 5, and 7 after the first injection. The 13CO2 excreted from the RIM rat was significantly increased on day 7. The RIM rat exhibited an acceleration of small intestinal transit on day 5. Fecal water content collected from the RIM rat was significantly increased on days 3 and 5. The amount of noradrenaline was significantly decreased in GI tissues on days 3, 5, and 7 in the RIM rat. Conclusions This study revealed that accelerated gastric emptying, accelerated small intestinal transit, and increase in fecal water content coexist with mechanical allodynia in the RIM rat, simulating the coexistence of chronic pain and alterations of GI function in patients with FM.
BACKGROUND:Fibromyalgia (FM) is a disorder characterized by widespread chronic pain as core symptom and a broad range of comorbidities. Despite the prevalence of gastrointestinal (GI) comorbidities in patients with FM, GI functions have rarely been investigated in animal models of FM. AIMS: The purpose of the present study is to investigate the coexistence of alterations of GI function in the reserpine-induced myalgia (RIM) rat, a validated FM model associated with disruption of monoamine system. METHODS: Paw withdrawal threshold (von Frey hair test) was assessed as pain-associated indicator. Gastric emptying (13C breath test), small intestinal transit (charcoal meal test), and fecal water content were investigated as GI functions. RESULTS: The specific regimen of reserpine for the RIM rat, i.e., 1 mg/kg s.c., once daily for three consecutive days, caused a reduction of paw withdrawal threshold (i.e., mechanical allodynia) on days 3, 5, and 7 after the first injection. The 13CO2 excreted from the RIM rat was significantly increased on day 7. The RIM rat exhibited an acceleration of small intestinal transit on day 5. Fecal water content collected from the RIM rat was significantly increased on days 3 and 5. The amount of noradrenaline was significantly decreased in GI tissues on days 3, 5, and 7 in the RIM rat. Conclusions This study revealed that accelerated gastric emptying, accelerated small intestinal transit, and increase in fecal water content coexist with mechanical allodynia in the RIM rat, simulating the coexistence of chronic pain and alterations of GI function in patients with FM.
Entities:
Keywords:
Fecal water content; Fibromyalgia; Gastric emptying; Gastrointestinal monoamines; Intestinal transit; Reserpine-induced myalgia rat
Authors: Henry C Lin; Corynn Neevel; Peng-Sheng Chen; Gina Suh; Jin Hai Chen Journal: Am J Physiol Gastrointest Liver Physiol Date: 2003-12 Impact factor: 4.052
Authors: R Schoonjans; B Van Vlem; N Van Heddeghem; W Vandamme; R Vanholder; N Lameire; R Lefebvre; M De Vos Journal: Neurogastroenterol Motil Date: 2002-06 Impact factor: 3.598