Brief Article
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World J Gastroenterol. Nov 21, 2010; 16(43): 5481-5489
Published online Nov 21, 2010. doi: 10.3748/wjg.v16.i43.5481
Brain activity following esophageal acid infusion using positron emission tomography
Shigeyuki Kobayashi, Yasuhiko Abe, Manabu Tashiro, Tomoyuki Koike, Katsunori Iijima, Akira Imatani, Shuichi Ohara, Satoshi Watanabe, Shin Fukudo, Tooru Shimosegawa
Shigeyuki Kobayashi, Yasuhiko Abe, Tomoyuki Koike, Katsunori Iijima, Akira Imatani, Shuichi Ohara, Tooru Shimosegawa, Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8574, Japan
Manabu Tashiro, Division of Cyclotron Nuclear Medicine, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi 980-8574, Japan
Satoshi Watanabe, Shin Fukudo, Division of Behavioral Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8574, Japan
Author contributions: Kobayashi S, Abe Y, Tashiro M, Koike T and Ohara S designed and carried out the study; Kobayashi S, Abe Y, Tashiro M, Koike T, Watanabe S and Fukudo S analyzed the data; Kobayashi S, Abe Y, Tashiro M, Koike T, Iijima K, Imatani A, Fukudo S and Shimosegawa T contributed to writing the paper.
Supported by (in part) A JST Grant on Research and Education in Molecular Imaging and Grant-in-Aid for Young Scientists (B), KAKENHI No. 19790465
Correspondence to: Yasuhiko Abe, MD, Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan. y_abe@mui.biglobe.ne.jp
Telephone: +81-22-7177171 Fax: +81-22-7177177
Received: July 11, 2010
Revised: August 28, 2010
Accepted: September 5, 2010
Published online: November 21, 2010
Abstract

AIM: To investigate symptoms and brain activity following esophageal acid infusion.

METHODS: Fifteen healthy volunteers were recruited for the study. Hydrochloric acid (pH 1 and 2) and distilled water (pH 7) were randomly and repeatedly infused into the esophagus. The brain activity was evaluated by positron emission tomography. The severity of heartburn elicited by the infusion was rated on an auditory analog scale of 0-10.

RESULTS: The severity of heartburn following each infusion showed a step-wise increase with increasing acidity of the perfusate. The heartburn scores were significantly higher in the second pH 1 infusion compared with the first infusion. Acid and distilled water infusion induced activation of various brain areas such as the anterior insula, temporal gyrus, and anterior/posterior cingulate cortex. At pH 1 or 2, in particular, activation was observed in some emotion-related brain areas such as the more anterior part of the anterior cingulate cortex, parahippocampal gyrus, or the temporal pole. Strong activation of the orbitofrontal cortex was found by subtraction analysis of the two second pH 1 infusions, with a significant increase of heartburn symptoms.

CONCLUSION: Emotion-related brain areas were activated by esophageal acid stimulation. The orbitofrontal area might be involved in symptom processing, with esophageal sensitization induced by repeated acid stimulation.

Keywords: Esophageal acid infusion, Brain imaging, Positron emission tomography