Subanesthetic Dose of Ketamine Increases Mitochondrial Respiration in Human Neurons

Abstract

Background: Subanesthetic doses of ketamine have rapid and robust antidepressant effects. However, the mechanisms underlying the antidepressant response are not fully understood. In pre-clinical models, brain-derived neurotrophic factor (BDNF) plays a major role in its antidepressant activity and BDNF is known to enhance neuronal bioenergetics. Here, we have investigated the effects of ketamine on cellular respiration in vitro using the human neuroblastoma cell line, SK-N-SH. Method(s): Before measurement, cells were differentiated for 5 days with retinoic acid. We performed mitochondrial stress tests on live SK-N-SH cells after treatment with 0-100 uM racemic ketamine. Oxygen consumption rate (OCR) and extracellular acidification rate (ECR) were measured in 30,000 cells per well, with four replicates per dose, using a Seahorse XFe24 Analyzer. Fluoro-carbonyl cynade phenylhydrazon (FCCP) was added to probe the maximal respiratory capacity of the cells. We compared OCR and ECR with t-tests before and after FCCP. Result(s): OCR was significantly different in the cells treated with 10 compared to 100 uM racemic ketamine, both before (t(6) = 3.0, p = 0.02) and after (t(6) = 2.6, p = 0.04) the addition of FCCP while no significant differences were found between ECR between the 10 and 100 uM ketamine treatment groups at the times measured. Conclusion(s): Ketamine dosage correlated positively with oxygen consumption rate without affecting lactate production. These results indicate that ketamine may enhance oxidative cellular metabolism. We hope to further test our findings in human cortical spheroids derived from induced pluripotent stem cells. Supported By: Pappajohn Biomedical Institute & Iowa Neuroscience Institute Keywords: Depression, Ketamine, Energy metabolism, Neurons Cell Culture, Mitochondrial FunctionCopyright © 2020