The influence of environmental stressors on the pathogenesis of gastrointestinal disease has received increased awareness. Stress affects different physiological functions of the gastrointestinal tract, including gastric acid secretion and mucosal blood flow. Repeated exposures of rapid-onset, highly-sustained hypergravity cause severe physical stress in the pilot. Although the effects of exposure to hypergravity on cardiovascular and cerebral functions have been the subjects of numerous studies, crucial information regarding pathophysiological changes in the gastrointestinal tract following hypergravity exposure is lacking. In this study, we investigated the effects of acute exposure to hypergravity on gastric secretory activity and gastrin release. Male Sprague-Dawley rats were exposed to +10Gz three times for 3 min. Gastric juice and blood were collected. The volume and total acidity of gastric juice, and the plasma gastrin level was measured. Acute exposure to +10Gz significantly decreased the gastric juice parameters. The gastric juice volume and total acidity of hypergravityexposed rats were 3.54 ± 0.32 mL/100 g and 84.90 ± 5.17 mEq/L, respectively, which were significantly lower than those of the nonexposed rats (4.62 ± 0.39 mL/100 g and 97.37 ± 5.42 mEq/L; P < 0.001 and P < 0.001, respectively). In contrast, plasma gastrin level was not significantly altered following hypergravity exposure. We demonstrated that acute exposure to hypergravity led to a significant decrease in the gastric juice volume and acidity but did not alter the plasma gastrin level.
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The views and opinions expressed in this article are those of the authors and do not reflect the official policy or position of the Republic of Korea Air Force. The authors would like to thank Drs. Choong Sik Oh and Hye Sik Yun (Republic of Korea Air Force Aerospace Medical Center, Cheongju, Chungcheongbuk-do, Republic of Korea) for their technical assistance in conducting preliminary animal experiments. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2016R1D1A1B03935584) and by a faculty research grant of Yonsei University College of Medicine for 2016 (6-2016-0130).
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