FBJ Murine Osteosarcoma Viral Oncogene Homolog B (FOSB)

Delta FosB is a truncated splice variant of FosB. Delta FosB has been implicated in the development of drug addiction and control of the reward system in the brain, and is linked to changes in a number of other gene products such as CREB and sirtuins.

"Delta FosB" levels have been found to increase upon the use of cocaine. Each subsequent dose of cocaine will continue to increase the levels of Delta FosB with no ceiling of tolerance. Increasing the levels of Delta FosB has led to increases in "Brain-Derived Neurotrophic Factor" (BDNF) levels, which in turn will increase the number of dendritic branches and spines present on neurons involved with the nucleus accumbens and prefrontal cortex areas of the brain.