Receptors make a quick exit

When neurons sense a long-term need for more glutamate receptors, they make a form that speeds through the trafficking network to get to the synapse quickly, according to results from Yuanyue Mu, Michael Ehlers, and colleagues (Duke University, Durham, NC).

Regulating the number of synapse-localized glutamate receptors, including those of the NMDAR variety, is one major strategy for controlling signaling from that synapse. In the short term, decreased synaptic activity promotes the loss of NMDARs and vice versa. But over the long haul, the number of NMDARs is up-regulated at quiet synapses.

Ehlers' group now demonstrates that this enduring modification is a result of selective mRNA splicing to produce a fast-moving NMDAR variety. Preventing neuronal firing (with sodium channel blockers) increased synaptic NMDARs by increasing the proportion of newly...