Related Experiment Videos
Hypothalamic control of amino acid appetite
Annals of the New York Academy of Sciences
|February 4, 1999
Summary
Protein malnutrition affects taste preferences. Rats deficient in lysine showed reduced umami taste preference, suggesting the brain recognizes nutrient deficits and umami preference may indicate adequate protein nutrition.
Area of Science:
- Neuroscience
- Nutritional Science
- Sensory Science
Background:
- Taste preference for umami substances like MSG is influenced by protein nutrition.
- Dietary protein or essential amino acid (AA) deficiency, specifically L-lysine (Lys), alters taste preferences in rats, reducing their liking for umami compounds.
Purpose of the Study:
- To investigate the link between protein malnutrition and umami taste preference.
- To identify the brain regions involved in recognizing nutrient deficits and their effect on taste perception.
Main Methods:
- Rats were fed diets deficient in protein or L-lysine (Lys).
- Taste preferences were assessed by observing food consumption.
- Functional magnetic resonance imaging (fMRI) was used to localize brain activity.
- Single neuron activity in the hypothalamus was recorded.
Main Results:
- Lys-deficient rats consumed less umami substances compared to normally nourished rats.
- The ventromedial (VMH) and lateral (LHA) hypothalamus were identified as key brain regions for deficit recognition.
- Neuronal plasticity was observed in the LHA, with cells showing specific responses to Lys in deficient rats.
- Neurons in nondeficient rats responded differently to monosodium L-glutamate (MSG).
Conclusions:
- The LHA and VMH play crucial roles in identifying nutrient deficiencies.
- Hypothalamic neural plasticity contributes to maintaining amino acid homeostasis.
- A preference for umami taste may serve as an indicator of adequate protein nutrition, applicable to both rats and humans.