Removing the PKCI/HINT1 gene from mice has an anti-depressant-like and anxiolytic（抗焦虑药）-like effect. Researchers writing in the open access journal BMC Neuroscience applied a battery of behavioral tests to the PKCI/HINT1 knockout animals, concluding that the deleted gene may have an important role in mood regulation. Elisabeth Barbier and Jia Bei Wang, from the School of Pharmacy at the University of Maryland, USA, carried out the experiments to investigate the role of the gene in regulating mood function. Wang, the corresponding author of the paper, said, "The knockout mice displayed behaviors indicative of（表现出） changes in mood function, such as increased perseverance（毅力，忍耐） and reduced anxiety in open spaces".

The causes of mood dysfunction（机能障碍）, as seen in depressive and bipolar disorders（躁郁症）, are still not fully understood. They are believed to be multifactorial（多因子的）, involving heredity（遗传）, changes in neurotransmitter（神经传递素） levels, altered neuro-endocrine（内分泌） function, and psychosocial factors（社会心理因素）. Speaking about these results, Wang said, "Although we don't yet know why the deletion of the gene altered the mood status of the mice, what we have learned about the importance of this gene in mood function and its involvement in human mental disorders（精神障碍） is interesting. The protein encoded by this gene could be a potential drug target for development of diagnostic or therapeutic agents（治疗剂） that one day might be used for depression, bipolar or schizophrenia（精神分裂症） disorders. In addition, the knockout mice（基因剔除小鼠） might be useful as a model to study mania（狂躁）, as there is no other animal model available yet.