MedicalResearch.com Interview with:
Ana-Clara Bobadilla, Ph.D.
in the laboratory of Peter Kalivas, Ph.D
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The Brain-derived neurotrophic factor (BDNF) is a growth factor that has well-described effects in the survival, growth and differentiation of neurons during development of the central nervous system, but it also maintains a role during adulthood in learning, memory and various disorders such as addiction. Several clinical studies show increased BDNF levels in the serum of cocaine- or alcohol-dependent patients compared to controls (D’Sa et al., 2011; D’Sa et al., 2012). In preclinical research, a wealth of studies shows that chronic exposure to drugs of abuse impacts BDNF expression in different parts of the brain, including the main regions comprised in the reward circuitry, the cortex and the nucleus accumbens (for a comprehensive review, see Li & Wolf, 2015). Conversely, altering BDNF expression or transmission has profound effects on the response of the brain to drugs (see McGinty et al., 2010). Importantly, BDNF effects are often region-specific, meaning that an increase in BDNF expression in one region can decrease the effects of drug exposure in the brain while the same increase in another region can have opposite effects (Li et al., 2013). Because BDNF transmission can modify the expression of a wide range of genes leading to long-term modifications, numerous studies administer BDNF early in the drug exposure protocol and focus on the long-term changes induced by the growth factor.
In this study, we microinjected BDNF directly in the nucleus accumbens minutes before measuring cocaine craving in a well-known rodent model of relapse. We found that BDNF induces a robust decrease in craving that lasts for at least 3 days post-treatment. The inhibitory effect of BDNF is not seen when animals are tested for sucrose, a very strong reward for rats, suggesting that this effect is specific to cocaine.
Moreover, cocaine craving is only decreased when BDNF is microinjected before the craving test, but has no effect when injected a day before the craving test or in the home cage, indicating a time-specificity in addition to the region-specificity previously described. Continue reading