BACKGROUND & AIMS: Psychological stress in early childhood has been implicated in the pathophysiology of functional dyspepsia but the mechanism is unclear. This study investigates the effect of early psychological stress on the regulation of satiety function in adulthood using an animal model of neonatal maternal separation stress (NMSS). / CONCLUSIONS: Psychological stress in early life leads to aberrant ghrelin profile and dysregulation of feeding behavior in response to acute psychological or physiological stress in adulthood. / METHODS: Sprague-Dawley (SD) rats underwent 3-hour daily maternal separation (MS) from postnatal day 2 to 22 and were weaned. The rats with no MS served as non-handling controls. Three experiments were conducted on these rats on day 60: (1) Water avoidance stress (WAS); (2): Feeding after overnight fasting and (3) Feeding after overnight fasting and WAS. Serial blood samples were collected for acylated ghrelin (AG) assay. In experiments (1) and (2), tissues from the stomach and hypothalamus were harvested additionally for evaluation of ghrelin expression. In experiments (2) and (3), calorie intake was also monitored at regular time intervals. / RESULTS: Experiment (1): MS rats had significantly higher mRNA ghrelin in hypothalamus (1.012 +/- 0.098 vs 0.618 +/- 0.071, P = 0.009) and plasma AG level (141.6 +/- 28.92 pg/mL vs 97.69 +/- 38.21 pg/mL, P = 0.014) in baseline non-stressed conditions. After WAS, MS rats had further increase in plasma AG level and gastric ghrelin expression. Experiment (2): After overnight fasting, the initial calorie intake was significantly higher in MS rats (at 3 mins: 1.303 +/- 0.293 kcal vs 0.319 +/- 0.159 kcal, P= .011; at 8 mins: 2.578 +/- 0.207 kcal vs 1.299 +/- 0.416 kcal, p = 0.019) but it dropped abruptly afterward and no difference in overall calorie intake over 28 minutes was found. The postprandial plasma AG level and gastric mRNA ghrelin were significantly lower in MS rats (95.92 +/- 12.71 pg/mL vs 154.01 +/- 14.53 pg/mL, p = 0.010). Experiment (3): After both fasting and WAS, the MS rats had significantly higher calorie intake in the first hour (17.24 +/- 1.10 kcal vs 11.95 +/- 1.20 kcal, P= 0.006) but it dropped substantially afterward with significantly lower cumulative calorie intake at 3 hours (at 3 hr: 19.44 +/- 1.50 kcal vs 26.49 +/- 2.25 kcal, P = 0.023). The calorie intake in MS rats remained significantly lower than that of controls up to 48 hours (168.1 +/- 4.76 kcal vs 220.8 +/- 8.27 kcal, P< 0.001). / Cheung, Kwan Yui Cynthia. / Adviser: Justin C.Y. Wu. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 138-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.