Laurent Nguyen’s team has demonstrated the role of glycine in the migration of cortical interneurons.  This study is a new illustration of the function of neurotransmitters during early stages of development, before the establishment of synaptic transmission and therefore the conduction of nerve impulse. This discovery demonstrates the importance of the environment on the control of the migration of these nerve cells.

Neurotransmitters are veritable chemical messengers which ensure the transmission of nerve impulse from one neuron to another. Communication between two nerve cells takes place by means of the synapse, which is a junction point between two neurons. Neurotransmitters, which are stored in presynaptic vesicles, are released in the synaptic cleft when the electric signal reaches the outer edge of the neuron. In this way the electric message is transformed into a chemical signal before regaining its electric form when the neurotransmitters attach themselves to the following neuron. Initially discovered and understood in the context of this function of nerve communication, neurotransmitters have revealed another side to their function over the last twenty years.  “Various studies correlate the expression of neurotransmitters and their receptors during brain development, before the nerve connections are established. In this case the receptors are called extrasynaptic receptors”, explains Laurent Nguyen, a Research Associate at the FRS-FNRS and at WELBIO and who is also an investigator at GIGA-Neurosciences of the University of Liege. Laurent Nguyen’s team is interested in neuronal migration in the cortex and has set up a project aiming to define whether neurotransmitters play a role in the control of the migration of the interneurons of the cortex.

An investigation into the presence of glycine receptors

“We focused our attention particularly on a small amino acid, called glycine”, explains Laurent Nguyen. “We knew that this neurotransmitter and its receptor were expressed in the brain during development but we did not know what their functions were”. During his thesis, Laurent Nguyen had already worked on the role of neurotransmitters during development and their extrasynaptic functions.  “In particular, we showed that the stem cells of the central nervous system of rat embryos express glycine receptors. This time, in the context of Ariel Avila’s thesis, we chose to analyse the expression and function of glycine receptors in migrating interneurons”, continues Laurent Nguyen. The interneurons are inhibitor neurons and constitute one of two main classes of nerve cells found in the cortex, the other being projection neurons (Read The migration of neurons ‘under the wing’ of the Elongator).