Macronutrient-specific dietary selection in rodents and its neural bases

Area of Science:

• Neuroscience
• Nutritional Science
• Pharmacology

Background:

• Nutrient selection is a complex behavior influenced by various physiological and environmental factors.
• Understanding the neural basis of macronutrient selection is crucial for deciphering appetite regulation.
• Previous research has proposed roles for various neurotransmitters in mediating nutrient-specific intakes.

Purpose of the Study:

• To critically review the existing literature on drug-induced alterations in macronutrient selection.
• To identify reliable evidence for neurotransmitter involvement in specific macronutrient appetite regulation.
• To highlight gaps in knowledge regarding the neural pathways underlying nutrient selection.

Main Methods:

• Comprehensive literature review of studies investigating drug effects on macronutrient selection in animal models.
• Analysis of studies employing sensorily distinct macronutrient forms and varied dietary compositions or animal strains.
• Evaluation of evidence for neurotransmitter agonists and antagonists on dietary intake patterns.

Main Results:

• Limited evidence supports reliable drug-induced alterations in macronutrient selection.
• D-norfenfluramine, fluoxetine, and paraventricular serotonin (5-HT) consistently reduced dextrin intake in rodents.
• Serotonergic agents showed the clearest reversal of effects between agonists and antagonists; other neurotransmitter claims were unsubstantiated.

Conclusions:

• Serotonergic pathways represent a potential target for modulating macronutrient selection, specifically carbohydrate intake.
• Claims regarding catecholaminergic, opioid, and peptidergic involvement in protein and carbohydrate intake require further substantiation.
• Future research must elucidate the specific neural pathways and sensory cues involved in drug-mediated nutrient selection.