Synaptic plasticity, or long-term potentiation (LTP), of excitatory synapses in the hippocampus contributes to learning and the establishment of spatial memories. In the CA1 region, induction of LTP enhances the function of postsynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs) because of the Ca2+-calmodulin kinase II (CaMKII)-dependent phosphorylation of this subtype of glutamate receptor. Entry of Ca2+, via N-methyl-d-aspartate receptors (NMDARs), during strong synaptic stimulation provides the stimulus to trigger phosphorylation of AMPARs. However, this induction also requires activation of a protein kinase C (PKC)-dependent tyrosine kinase signal cascade and a concomitant upregulation of NMDARs. This review focuses upon NMDARs as potential targets of PKC and / or of the PKC-dependent tyrosine kinase cascade. PKC, acting via the CAK beta / Src tyrosine kinase cascade, enhances NMDAR activation and may increase the number of receptors expressed in synapses. In contrast, direct phosphorylation of NMDARs by PKC increases the sensitivity of NMDA channel inactivation to intracellular Ca2+. In CA1 neurons, PKC provides a point of convergence of control of NMDARs and synaptic plasticity for a wide variety of G-protein coupled and growth factor receptors.
Current Drug Targets aims to cover the latest and most outstanding developments on the medicinal chemistry and pharmacology of molecular drug targets e.g. disease specific proteins, receptors, enzymes, genes. Each issue of the journal will be devoted to a single timely topic, with series of in-depth reviews, written by leaders in the field, covering a range of current topics on drug targets. These issues will be organized and led by a guest editor who is a recognized expert in the overall topic. As the discovery, identification, characterisation and validation of novel human drug targets for drug discovery continues to grow; this journal will be essential reading for all pharmaceutical scientists involved in drug discovery and development.