Nerve cells (green) connect with muscle cells at junctions called synapses (red). These junctions are essentially the communication sites, where the nerves release chemicals (neurotransmitters) that tell individual muscles to contract. To put it another way, nerve-muscle synapses allow the brain to tell the body what to do – dance, jump, breathe, blink, whatever. For years, it was believed that one neurotransmitter –acetylcholine – controlled the development of these junctions, which is completed within the first few weeks of life. But now scientists have discovered that a second factor – glutamate – is also required. Glutamate is by far the most abundant neurotransmitter within the brain, but until now its role in nerve-muscle junction formation had been overlooked. After a serious nerve injury, reinstating developmental pathways is considered to be necessary for regenerating broken connections. The findings therefore suggest that manipulating glutamate signalling may a valuable and unexplored means for treating patients with paralysis.
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