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Preloads of corn oil inhibit independent ingestion on postnatal day 15 in rats
A Weller1, I H Gispan, R Armony-Sivan
1Department of Psychology, Bar Ilan University, Ramat Gan, Israel.
Insights
Young rats develop the ability to reduce food intake after a fatty meal as they mature. This postingestive control is mediated by fats and involves cholecystokinin (CCK).
Area of Science:
- Physiology
- Neuroscience
- Developmental Biology
Background:
- Understanding the development of appetite regulation is crucial for addressing feeding disorders.
- Postingestive feedback mechanisms play a significant role in controlling food intake.
- The role of specific nutrients and hormones in early-life satiety is not fully understood.
Purpose of the Study:
- To investigate the ontogenetic development of postingestive inhibitory control of ingestion in preweaning rats.
- To determine if the inhibitory effect of an oil preload is due to its fat content or texture.
- To examine the involvement of cholecystokinin (CCK) in this developmental process.
Main Methods:
- Preweaning rats received gastric preloads of water, mineral oil, or corn oil.
- Ingestive behavior was measured by milk intake in a 30-min test.
- The effect of a cholecystokinin-A (CCKA) receptor antagonist (devazepide) was assessed.
Main Results:
- Corn oil preloads significantly decreased milk intake on postnatal days 15 and 18, but not on day 12.
- Corn oil was more effective in reducing intake than mineral oil, suggesting a role for fat content.
- Devazepide pretreatment significantly attenuated the inhibitory effect of corn oil, indicating CCK mediation.
Conclusions:
- Postingestive inhibitory control of ingestion in rats develops during the preweaning period.
- The fat content of a preload, rather than its oily texture, is primarily responsible for the inhibitory effect.
- Cholecystokinin (CCK) plays a significant role in mediating this fat-induced satiety during development.
Abstract:
The ontogenetic development of postingestive inhibitory control of ingestion by an oil preload was examined in preweaning rats. Gastric preloads (5% b.wt) of water, mineral oil or corn oil were administered 5 min before a 30-min intake test in which pups licked milk from the floor of a test chamber. Preloads of corn oil decreased intake significantly compared with preloads of mineral oil or water on Postnatal Days 15 and 18, but not on Postnatal Day 12. Because preloads of corn oil reduced intake ore than preloads of mineral oil, it is possible that the inhibitory effect of corn oil is due to its fats rather than to its oily texture. Cholecystokinin (CCK), presumably released from the small intestine, apparently mediates part of this inhibitory effect because pretreatment with devazepide, a specific CKKA antagonist, significantly reduced the inhibition produced by corn oil.