Researchers shed light on life/death switch in nerve cells
European researchers have uncovered why a receptor on our nerve cells sometimes promotes cell survival and sometimes causes cell death. The study, which was partly funded by the EU under the Sixth Framework Programme (FP6), is published in the latest edition of the journal Neuron. The receptor in question is called N-methyl-D-aspartate (NDMA), and as a promoter of cell survival it plays a key role in learning and memory processes. However, it can also promote cell death and NMDA receptor activation is the leading cause of neuron death associated with head injuries and seizures. NMDA receptors have also been implicated in neurodegenerative disorders such as Huntington's and Alzheimer's. For a long time researchers have been eager to find out the reasons behind NMDA's apparently contradictory behaviour. The researchers used Gene-Chip-Technology to analyse thousands of genes, and identified two distinct, largely non-overlapping groups of genes which are activated by the NMDA receptor, one leading to cell death and the other to cell survival. The key to which set of genes is triggered is the location of the NMDA receptor on the cell. NMDA receptors on synapses (the 'junctions' of nerve cells where nerve signals are transmitted from one cell to another) promote the production of pro-survival signals. Meanwhile NMDA receptors on other parts of the cell surface trigger genes that lead to the death of the neuron. The researchers believe that their discovery opens up the prospect of new therapies for the treatment of degenerative diseases of the nervous system such as Alzheimer's and Parkinson's.