Submitted on October 20, 2007
Accepted on January 1, 2008
Fixed feeding potentiates interdigestive gastric motor activity in rats: importance of eating habits for maintaining interdigestive MMC
Hajime Ariga1, Kenji Imai2, Cindy Chen, Christopher Mantyh3, Theodore N. Pappas4, and Toku Takahashi5*
1 Surgery, Duke university, Durham, North Carolina, United States
2 Surgery, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, North Carolina, United States
3 surgery, duke university, Box 3117, durham, North Carolina, 27710, United States
4 Department of Surgery, Duke University Medical Center, Durham,, North Carolina, United States
5 Division of Experimental Surgery, Duke University, VA Medical Cener, Surgical Service (112), Durham, North Carolina, United States
* To whom correspondence should be addressed. E-mail: ttakahashi{at}mcw.edu.
Endogenous ghrelin regulates the occurrence of interdigestive gastric phase III-like contractions in rats. However, the fasted motor pattern is not so regular and potent as humans and dogs. We hypothesize that eating habits play an important role in maintaining a regular interdigestive gastric contractions. We studied the effect of fixed-feeding regimen on interdigestive gastric contractions and plasma acyl ghrelin levels. The fixed-fed rats were trained to the assigned meal feeding regimen, once daily at 12:00 pm - 16:00 pm for 14 days. Free-fed rats were maintained with free access to food. As ghrelin regulates gastric emptying as well, solid gastric emptying was also studied in fixed fed rats and free-fed rats. In free fed rats, 2 of 6 rats didn't show interdigestive gastric phase III-like contractions. In contrast, phase III-like contractions were observed in all rats 14 days after starting the fixed-feeding regimen. The maximal amplitude of phase III-like contractions significantly increased from 8.4 ± 0.6g to 16.3 ± 1.8g (n=6, P<0.05) 14 days after starting the fixed-feeding. Fasted and postprandial plasma ghrelin levels were significantly increased 14 days after fixed feeding. Solid gastric emptying was significantly accelerated in fixed fed rats (72.1 ± 4.2%), compared to that of free-fed rats (58.7 ± 2.7%, n=6, P<0.05). Our current findings suggest that fixed feeding increases plasma ghrelin levels, potent interdigestive contractions and acceleration of gastric emptying.
