The Role of Kappa-Opioid Receptor/Dynorphin System in Modulating Neural-Circuits of Depression and Anxiety-A Review.

Major depression and anxiety disorders are psychiatric disorders that involve a great number of people. There is a growing need for new and better pharmacological treatments for these diseases. Kappa-opioid receptor (KOR) antagonists seem to be a promising new pathway for the development of new antidepressants and anxiolytics, but a great challenge is understanding how the various neural circuits work and to what degree they are influenced by KOR modulators. This narrative review is focussed on two main circuits: the Hippocampus-Amygdala-Prefrontal Cortex and the Ventral Tegmental Area-Nucleus Accumbens. The relevant neuroanatomy, their role in modulating behaviour and how KOR modulators can alleviate these diseases are discussed. Concluding, a more holistic understanding of the circuits influenced by the KOR/Dyn system is relevant for developing new therapies. In non-clinical pharmacology addressed to the KOR/Dyn system, variables such as age, sex and social hierarchy rank can influence experimental outcomes.