January 23, 2006
Brain-derived neurotrophic factor, or BDNF, plays a critical role in learning and memory. It does so biochemically by binding to and signaling through the so-called TrkB receptor displayed on the surface of neurons. This precise interaction helps neurons to modulate the strength of the signals transmitted through their synapses, which in turn promotes the needed synaptic plasticity involved in learning and memory. In the January 4 issue of the Journal of Neuroscience, NIDCR grantees and colleagues report that BDNF-TrkB signaling complex also plays an important and previously undiscovered role within the brain stem in the development of pain hypersensitivity. According to the authors, after a tissue injury, the BDNF-TrkB complex in the brain stem can trigger facilitating, rather than inhibitory, signals back to the spinal cord. This facilitating signal allows the related pain-processing circuitry associated with the spinal cord to amplify and spread the sensation of pain. They note that their discovery raises the possibility that BDNF-based therapies for degenerative disorders of the central nervous system “could lead to undesirable central pain.”