In order to confirm these results, the scientists used genetically modified animals in which the alpha 2 subunit is not expressed. “In these animals that have been deprived of glycine alpha 2 homomeric receptors, we also observe a default migration of interneurons in the cortex”, explains Laurent Nguyen.

The environment, a key factor in migration

The present study is a new illustration of the function of neurotransmitters at early stages of development, before the establishment of the synaptic transmission and therefore the conduction of the nerve impulse. “In the present case, the glycine controls the movement of the interneurons, this is the first time that we have worked on signals that are external to the cell. Elongator and p27 are molecules that are directly expressed by the neurons while the glycine is liberated by other cells”, continues the researcher (see articles “The migration of neurons ‘under the wing’ of the Elongator” and “The migration of cortical interneurons”). This discovery makes it possible to demonstrate the importance of the environment on the control of the migration of these nerve cells. “There is a complementarity between all these molecules which intervene in this process and it is extremely important that everything is well orchestrated to ensure that it works”, concludes Laurent Nguyen.

This basic research leads to an increased understanding of the mechanisms that govern the development of the cortex and therefore illnesses linked to mutations which affect the molecular pathways involved. Recent work has notably shown that certain mutations of genes coding for various neurotransmitter receptor subunits play a role in the occurrence of epilepsy, schizophrenia and autism.