Figure 2.

Late-phase NMDA dependent-LTP. In this stage, (1, 2) Ca²⁺ ions inside the cell recruit adenyl cyclase to produce cAMP. (3, 4) Cyclic adenosine monophosphate, in turn, activates PKA that switches on MAPK. (5) This kinase is translocated to the nucleus and phosphorylates CREB-1, an important transcription factor. (6, 7) The phosphorylation activates CREB-1, resulting in increased transcription of a number of target genes and their subsequent translation into proteins responsible for the formation of new synaptic connections.