Knuckey N W, Fowler A G, Johanson C E, Nashold J R, Epstein M H
Department of Clinical Neurosciences, Brown University/Rhode Island Hospital, Providence.
J Neurosurg. 1991 Jun;74(6):965-71. doi: 10.3171/jns.1991.74.6.0965.
Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting 22Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of 22Na dialyzed. This hypothesis is supported by the 22Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the 22Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system.
微透析技术用于在体测量脑间质液中的化合物。作者描述了该技术在中枢神经系统的另一种应用，即在大鼠的大池进行微探针透析，以研究离子转运和脑脊液（CSF）生成的动力学。脉络丛是脑脊液的主要来源，脑脊液是通过钠从血液主动转运至脑室而产生的。脑脊液的生成与钠从血液到脑脊液的转运直接相关。通过将22Na注入体循环，并通过微透析定量其进入脑脊液的移动情况，可以可靠地估计脑脊液生成速率的变化。该系统的灵敏度通过给予乙酰唑胺（一种脑脊液生成的标准抑制剂）来确定。由于已知乙酰唑胺可使脑脊液生成减少40%至50%，因此用该药物治疗的动物的大池微透析系统应能检测到透析出的22Na量相应减少。对照动物与治疗动物的22Na摄取曲线支持了这一假设：即，乙酰唑胺使示踪剂进入透析液的速率和程度平均降低约45%。布美他尼（一种袢利尿剂）使进入透析液的22Na减少了30%。因此，大池液体的微探针透析是一种微创且经济的方法，用于评估药物和激素对脉络丛-脑脊液系统的影响。
