Memory coding and retention:: Brain-derived neurotrophic factor (BDNF) in synaptic plasticity

Introduction. It has been suggested that the long-term modifications that take place in synaptic transmission constitute the foundation of the processes by which information stored. The neurotrophin called brain-derived neurotrophic factor (BDNF) has recently emerged as a powerful molecular mediator in central synaptic plasticity. Development. In this work we review the studies that have represented a significant step forward in explaining the role played by BDNF in long-term synaptic plasticity. The effects of BDNF on synaptic plasticity can be of a permissive nature, whereby it establishes the conditions under which plastic changes can take place, or it may be instructive. In this latter case it exerts direct effects that bring about changes in the communication and morphology of the synapses. The actions carried out by BDNF include its capacity to contribute to the stabilisation and maturation of already-existing synapses, as well as to generate new synaptic contacts. One important finding that highlights the participation (of this neurotrophin in synaptic plasticity is the observation that adding BDNF gives rise to drastic long-term increases in synaptic transmission, similar to the long-term potentiation in the hippocampus and neocortex of mammals. Conclusions. Because BDNF modulates both the electrical properties and the structural organisation of the synapse, this neurotrophin has been considered to be an important marker during learning and memory processes. [REV NEUROL 2007; 45: 409-171