Objective To investigate the effects of different concentrations of ketamine on the apoptosis of cultured spinal dorsal horn neurons and astrocytes induced by glutamate. Methods Newborn Wistar rats (1-3 days old) weighing 10-15 g were used in this study. The animals were anesthetized and the dorsal hom of T11-L5 segment of the spinal cord was separated under sterile condition. The neurons and astrocytes were obtained by trypsin digestion of the tissue and mixed and cultured for 2 weeks. The cells were then randomly divided into 6 groups ( n = 8 each) : control group (C) in which Hank solution 50 ?l was added; glutamate group (G) glutamate was added (the final concentration was 100 ?mol?L-1); ketamine group (K) ketamine was added (final concentration = 1 mmol?L-1) and glutamate-ketamine groups (GK1 , GK2, GK3) glutamate was added first (final concentration was 100 ?mol?L-1) and 30 minutes later ketamine was added (the final concentration was 0.1, 1 or 10 mmol?L-1). After being incubated for 48 h the supernatant was harvested for determination of IL-1? and TNF-? concentrations. The morphological changes of the cells were examined by Wright staining. The apoptotic neurons and astrocytes were detected by flow cytometry.Results The number of apoptotic cells was significantly greater and the concentrations of IL-1? and TNF-? were significantly higher in group G and GK1 than in group C (P