Effects of interrupting an intraoral meal on meal size and meal duration in rats

Most experiments on satiation do not separate the contribution to meal size of cumulative intake from that of time since meal onset. To assess the relative contributions of temporal and intake factors, the amount consumed of intraorally infused 12.5% glucose solution, delivered at a fixed rate of 1.0 ml/min, was assessed after tests that were interrupted for variable durations (Experiments I and II) beginning at different times within the test meal (Experiment I). Rats' meal size did not vary despite the imposition of single or multiple pauses which interrupted ingestion for as long as 38 min. These results show that, within this paradigm, the duration of the meal varies in service of an intake "goal". Such a defense of meal size requires accurate monitoring of the postingestive load despite its redistribution by continued gastric emptying during the imposed pauses in ingestion.