The mechanism(s) responsible for the anti-inflammatory properties of ketamine are not known, but its neurological and psychotropic actions are believed primarily to be mediated by antagonism of NMDA receptors [21, 47] . Glutamate is the brain's primary excitatory neurotransmitter. NMDA receptors are found in many cell Bacteria were added at a final concentration of 10 5 to10 7 CFU/mL (retrospective confirmation) in the presence of vancomycin at 20 μg/mL. The ketamine concentration was 100 μM. Results are depicted as percentile reduction with 95% confidence intervals, i.e., the percent of TNF reduction at the specific exposure time that occurs in comparison to inoculation without ketamine at the same time. The "*" indicates statistically significant difference at p < 0.05.