No abstract

J. Neurochem. (2011) 116, 530–543. Abstract The use of hippocampal dissociated neuronal cultures has enabled the study of molecular changes in endogenous native proteins associated with long‐term potentiation. Using immunofluorescence labelling of the active (Thr286‐phosphorylated) alpha‐Ca2+/calmodulin‐dependent protein kinase II (CaMKII) we found that CaMKII activity was increased by transient (3 × 1 s) depolarisation in 18‐ to 21‐day‐old cultures but not in 9‐ to 11‐day‐old cultures. The increase in Thr286 phosphorylation of CaMKII required the activation of NMDA receptors and was greatly attenuated by the CaMKII inhibitor KN‐62. We compared the effects of transient depolarisation on the surface expression of GluA1 and GluA2 subunits of the alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptor and found a preferential recruitment of the GluA1 subunit. CaMKII inhibition prevented this NMDA receptor‐dependent delivery of GluA1 to the cell surface. CaMKII activation is therefore an important factor in the activity‐dependent recruitment of native GluA1 subunit‐containing alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptors to the cell surface of hippocampal neurons.