Dopamine neurons involved in palatable food consumption

Dopamine neurons involved in palatable food consumption

A research team investigated a group of neurons in the hypothalamus called NPY/AgRP, which are known to play a role in food intake. These neurons are part of the circuit that maintains energy balance: they promote food intake when they are activated, in case of fasting or hypoglycemia for example.
 
Until now they have been considered as key targets for developing obesity treatments. By studying mice lacking these neurons, the researchers have demonstrated that these are essential for triggering food intake when the food does not have high hedonic value and is simply a response to metabolic needs. By contrast, they contribute less to food intake when the food is very palatable, high in fats and carbohydrates.
 
When these neurons are absent or inhibited, the mice consume less standard food, even after fasting. By contrast, they will feed normally if given high-fat and high-carbohydrate food.
 
A series of experiments showed that when NPY/AgRP neuron activity is compromised, the hormone that stimulated them will instead activate neurons involved in the reward circuit. This dopamine-controlled nerve pathway therefore takes over and directs feeding behavior.
 
The result is a disturbed feeding pattern, disconnected from the body's energy needs and essentially dependent on the pleasure caused by food.
 
The mice studied then ate high-fat and high-carbohydrate foods in higher quantities and gained weight. Their feeding behavior was also much more sensitive to external factors such as stress. Overall, these mice are a good model of comfort feeding.
 
These results therefore shed new light on the role of NPY/AgRP neurones in maintaining energy balance. They also indicate that acting at a pharmacological level on these neurons to treat hyperphagia could be counter-productive.
Edited

Rating

Unrated
Rating: