Nutrient-Sensing Neurons

Using just three dopaminergic neurons, Drosophila larvae can sense whether a food source lacks a full roster of essential amino acids.

Tracy Vence
May 31, 2014

SOMETHING’S MISSING: Amino acid-sensing neurons (containing fluorescent calcium indicators) can detect nutrient deficiencies in a fruit fly’s food.© PIERRE LEOPOLD

EDITOR'S CHOICE IN NEUROBIOLOGY

The paper
M. Bjordal et al., “Sensing of amino acids in a dopaminergic circuitry promotes rejection of an incomplete diet in Drosophila,” Cell, 156:510-21, 2014.

The approach
Like other animals, Drosophila larvae—which normally eat ravenously—will avoid food lacking essential amino acids (EAAs), presumably to seek out meals that are more nutritious. This behavior is thought to rely upon amino acid sensors, likely in fat cells and neurons. To track down such a sensor, a team led by Pierre Léopold at the University of Nice–Sophia Antipolis monitored neural activity in brains isolated from Drosophila larvae.

The response
Léopold’s team saw dopaminergic neurons in the fruit fly brain immediately activate when bathed in a food solution lacking EAAs, but cease activity when EAAs returned. “We...