Environmental enrichment differentially regulates synaptic plasticity of hippocampal mature and newborn dentate granule cells and attenuates methamphetamine-induced behaviors.
📄 Abstract
Substance use disorder is characterized by compulsive seeking behavior that is associated with aberrant synaptic plasticity in mature neurons. Environmental enrichment (EE) has been shown to increase adult hippocampal neurogenesis and exert beneficial effects on addictive behaviors. However, the mechanisms of EE's effects on methamphetamine (METH)-induced synaptic plasticity in mature and newborn neurons remain unclear. We reported that EE decreased METH-induced seeking behavior with a decrease in the activity of mature granule cells and an increase in the number of newborn granule cells. Furthermore, the aberrant glutamatergic transmission in hippocampal mature and newborn granule cells was differentially regulated by EE. Moreover, EE restored the normal synaptic plasticity, accompanied by enhancement of brain derived neurotrophic factor (BDNF) expression. Importantly, the intervention of BDNF reversed the effects of EE on METH-induced reinstatement behavior and glutamatergic transmission in both mature and newborn cells. Finally, specifically knocking out the newborn neurons reversed the changes of EE in abnormal plasticity of mature neurons, as well as in seeking and cognitive behaviors. Taken together, regulating synaptic plasticity of mature and newborn neurons is involved in METH-induced seeking behavior and cognitive impairments, which highlights a critical role of adult neurogenesis in the treatment of METH addiction.