Alternative definition : KEGG: Hippocampal long-term potentiation (LTP), a long-lasting increase in synaptic
efficacy, is the molecular basis for learning and memory. Tetanic stimulation of afferents
in the CA1 region of the hippocampus induces glutamate release and activation of glutamate
receptors in dendritic spines. A large increase in [Ca2 ]i resulting from influx through
NMDA receptors leads to constitutive activation of CaM kinase II (CaM KII). Constitutively
active CaM kinase II phosphorylates AMPA receptors, resulting in potentiation of the
ionic conductance of AMPA receptors. Early-phase LTP (E-LTP) expression is due, in
part, to this phosphorylation of the AMPA receptor. It is hypothesized that postsynaptic
Ca2 increases generated through NMDA receptors activate several signal transduction
pathways including the Erk/MAP kinase and cAMP regulatory pathways. The convergence
of these pathways at the level of the CREB/CRE transcriptional pathway may increase
expression of a family of genes required for late-phase LTP (L-LTP).;