Whole-brain mapping reveals the divergent impact of ketamine on the dopamine system
bioRxiv Preprint Server – April 12, 2023
Source: bioRxiv
Summary
Ketamine, a transformative fast-acting antidepressant, surprisingly affects brain dopamine systems differently depending on the brain region. Using detailed brain mapping, researchers found that repeated exposure can decrease dopamine neurons in midbrain areas linked to behavior, while *increasing* them in the hypothalamus. This reveals a complex, region-specific impact on brain pathways and connections, offering crucial insights into its therapeutic actions.
Abstract
Ketamine is a multifunctional drug with clinical applications as an anesthetic, as a pain management medication and as a transformative fast-acting antidepressant. It is also abused as a recreational drug due to its dissociative property. Recent studies in rodents are revealing the neuronal mechanisms that mediate the complex actions of ketamine, however, its long-term impact due to prolonged exposure remains much less understood with profound scientific and clinical implications. Here, we develop and utilize a high-resolution whole-brain phenotyping approach to show that repeated ketamine administration leads to a dosage-dependent decrease of dopamine (DA) neurons in the behavior state-related midbrain regions and, conversely, an increase within the hypothalamus. Congruently, we show divergently altered innervations of prefrontal cortex, striatum, and sensory areas. Further, we present supporting data for the post-transcriptional regulation of ketamine-induced structural plasticity. Overall, through an unbiased whole-brain analysis, we reveal the divergent brain-wide impact of chronic ketamine exposure on the association and sensory pathways.