Determination of the extracellular glycine concentration in the rat spinal cord dorsal horn by quantitative microdialysis

Two quantitative microdialysis methods were used to determine the extracellular concentration of glycine in the dorsal spinal cord of halothane-anaesthetised rats. Extracellular glycine determined by zero net flux was 2.6+/-0.3 microM and by the zero flow method was 3.3+/-0.3 microM. For comparison the glycine content of cerebrospinal fluid was determined to be 6.4+/-1.1 microM. There was no correlation between the extracellular and the cerebrospinal fluid concentrations.