The review of literature data is presented on the problem molecular and cellular mechanisms of learning which is intensely studied for last decade using the long-term potentiation (LTP) model in the brain slices in vitro. The main attention is paid for molecular mechanisms of LTP induction and supporting phases in hippocampal structures on the pre- and postsynaptic levels especially for the involvement of transmitters and retrograde messengers in these processes. The role of protein kinase-dependent proteins phosphorylation and of peptides synthesis expression in the LTP development is discussed. The perspective directions of complex investigation of LTP molecular mechanisms are outlined which are useful for understanding the whole picture of neuronal plasticity lying it the basis of learning and memory processes.