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Preference and diet type affect macronutrient selection after morphine, NPY, norepinephrine, and deprivation
C C Welch1, M K Grace, C J Billington
1Department of Medicine, Department of Veterans Affairs Medical Center, Minneapolis, Minnesota 55417.
The American Journal of Physiology
|February 1, 1994
Summary
Orexigenic agents and food deprivation alter macronutrient selection in rats. Prior preference significantly influences dietary choices, demonstrating that feeding stimuli and diet availability impact food selection.
Area of Science:
- Neuroscience
- Behavioral Biology
- Nutritional Science
Background:
- Orexigenic agents like morphine, neuropeptide Y (NPY), and norepinephrine (NE) are known to influence macronutrient selection.
- Food deprivation (24-48 hours) and chronic dietary restriction are also reported to affect feeding behaviors, particularly macronutrient preference.
Purpose of the Study:
- To investigate the effects of specific orexigenic agents (morphine, NPY, NE) and different feeding deprivation states on macronutrient selection in rats.
- To determine how baseline dietary preference interacts with feeding stimuli and diet composition to influence food choices.
Main Methods:
- Rats were subjected to six experimental conditions: administration of morphine, NPY, NE, 24-hour food deprivation, 48-hour food deprivation, and chronic dietary restriction.
- Two dietary regimens were used: one with three macronutrient diets (carbohydrate, protein, fat) and another with two complete diets (high carbohydrate or high fat).
- Analysis of covariance was employed to account for the influence of baseline preference on feeding behavior.
Main Results:
- Morphine increased fat consumption, while NPY increased carbohydrate selection in both dietary regimens.
- Norepinephrine did not alter the selection of any specific macronutrient.
- Food deprivation led to increased fat consumption in regimen I and carbohydrate consumption in regimen II. Chronic restriction increased fat and protein intake in regimen I but had no effect in regimen II.
- Baseline preference significantly impacted dietary selection across most experimental conditions.
Conclusions:
- Dietary selection is a complex behavior influenced by the interplay of prior food preferences, specific feeding stimuli, and the available diet choices.
- The type of diet presented (macronutrient-specific vs. nutritionally complete) can modulate the effects of feeding stimuli and deprivation on macronutrient selection.