Figure 6.

Proposed model for NMDA receptor regulation by short- and long-term activation of 5-HT7 receptors. Prolonged (2 to 24 h) activation of 5-HT7 receptors up regulates PDGF receptor activation and expression in hippocampal neurons, cortical neurons, and SH-SY5Y cells. The upregulation of PDGFβ receptors is sufficient to inhibit NMDA-induced neuronal cell death in primary cultures. In addition, NMDA receptor subunit expression is reduced. In contrast, acute (5 min) activation of 5-HT7 receptors increases NMDA-evoked currents and differentially regulates NMDA receptor subunit phosphorylation and cell surface expression. Figure modified from [18].