Lindefors N, Amberg G, Ungerstedt U
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
J Pharmacol Methods. 1989 Nov;22(3):141-56. doi: 10.1016/0160-5402(89)90011-9.
Intracerebral microdialysis is a brain perfusion technique in which a tubular, semipermeable membrane perfused with a physiological solution is implanted into a selected brain region. Molecules in the extracellular space diffuse into the perfusate and may be recovered and their concentration determined. Hence, the level of substances such as neurotransmitters may be monitored, and the response to different treatments may be studied. The technique also allows for administration of substances locally to the region of the brain surrounding the perfused tubular membrane. Basic principles of the microdialysis technique are described, and the results from methodological experiments are examined. It is concluded that there is a direct linear relation between the concentration of a molecule in the medium surrounding the dialysis membrane and the concentration measured in the collected perfusate. Relative changes of molecular concentration in brain extracellular space may be calculated even when the molecular diffusion rate is unknown. In addition, a method is presented for calculating the real concentration of a substance in the extracellular space from its concentration in the perfusate. Applied in striatum of rat brain using microdialysis in vivo, the average extracellular concentration of the following substances is estimated to be: substance P, 0.9 nM; dopamine, 1 microM; and dihydroxyphenylacetic acid, 0.05 mM.
脑内微透析是一种脑灌注技术，将一根灌注生理溶液的管状半透膜植入选定的脑区。细胞外空间中的分子扩散到灌注液中，可被回收并测定其浓度。因此，可以监测神经递质等物质的水平，并研究对不同治疗的反应。该技术还允许在灌注管膜周围的脑区局部给药。描述了微透析技术的基本原理，并检查了方法学实验的结果。得出的结论是，透析膜周围介质中分子的浓度与收集的灌注液中测得的浓度之间存在直接线性关系。即使分子扩散速率未知，也可以计算脑细胞外空间中分子浓度的相对变化。此外，还提出了一种根据灌注液中物质的浓度计算细胞外空间中该物质实际浓度的方法。在大鼠脑纹状体中进行体内微透析应用时，估计下列物质的平均细胞外浓度为：P物质，0.9 nM；多巴胺，1 microM；二羟基苯乙酸，0.05 mM。
