A role for the mTOR pathway in surface expression of AMPA receptors

Delivery of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionate receptors (AMPARs) to the synapse is a critical factor controlling synaptic strength. It is now established that blockade of synaptic activity increases the surface expression of AMPARs. Factors modulating the delivery, insertion and expression of AMPARs are not completely known. Using immunohistochemical techniques, we first confirmed rapamycin-mediated inhibition of the mammalian target of rapamycin (mTOR) pathway in cortical neuronal culture. We then demonstrated that acute AMPAR activity blockade increased the synaptic expression of GluR2/3 subunits and rapamycin significantly reduced this expression. Our results suggest a role for the mTOR pathway in surface expression of AMPA receptors on cortical neurons.