Pregastric stimulation and cholecystokinin are not sufficient for the meal size-intermeal interval correlation in the rat

Abstract

Male albino rats with gastric fistula ate liquid food at the midpoints of the day or night phases of a 12:12 cycle after 3-hr food deprivation. During normal eating with fistula closed, rats (n=18) ate a mean meal size (MS) of 5.1 ml followed by a mean intermeal interval (IMI) of 67.2 min during the day, and rats (n=7) ate a MS of 3.0 ml followed by an IMI of 26.8 min at night. The MS and subsequent IMI correlated positively both in the day and night. When rats sham fed the first time with fistula open, the sham-fed MS was larger and IMI was shorter than were MS and IMI, respectively, when the fistula was closed during the night and day, and the MS-IMI correlation was absent in the day and night. When rats sham fed after intraperitoneal injection of 20% pure cholecystokinin (CCK) (day: 30 U/kg; night: 60 U/kg), sham-fed MS and IMI were not different from normal MS and IMI, respectively, when the fistula was closed during the night and day, but CCK failed to restore a normal MS-IMI correlation in the day or night. These results show that while certain food-contingent stimuli are potent for eliciting postprandial satiety including intermeal interval, preabsorptive pregastric stimuli and cholecystokinin may not be of major importance for the correlation between meal size and postprandial intermeal interval in the rat. © 1981.