TI - Nociceptive-activity induced cortical ERK1/2 activation in AMPA receptor subunit knockout mice . AB - Given the importance of both ERK and GluA1-containing AMPA receptors in plasticity phenomena in the ACC , we asked whether AMPA receptors could act upstream of nociceptive activity-evoked activation of ERK1/2 in the cortex . PHOSphorylation of ERK1/2 in neurons of the ACC induced by intraplantar injection of either formalin or CFA was significantly decreased in GluA1-/- mice in comparison with their WT mice ( see Fig 8A for typical example and Fig 8B for summary of densitometric analysis ) . In particular , dendrites of cortical neurons were rarely immunoreactive for pERK1/2 in formalin - or CFA-injected GluA1-/- mice . In contrast , nociceptive activity-evoked ERK1/2 PHOSphorylation of ERK1/2 remained intact in the ACC of GluA2-/- mice , as compared to WTCD1 mice ( not shown ) .