Significant correlation between cerebrospinal fluid and brain levels of norepinephrine, serotonin and acetylcholine in anesthetized rats

Acetylcholine Measurement of Cerebrospinal Fluid by In Vivo Microdialysis in Freely Moving Rats

“…Anesthesia was induced with 3076 halothane and was then maintained with 0.8% halothane in 21016 02 and 79% N2 with a precalibrated halothane vaporizer (Fluotec 3; Cyprane Keighley, Eng land). CSF samples for direct assay were collected as previously reported (9,10). In brief, the atlanto-occipital membrane was exposured under a microscope and a poly ethylene guide cannula described above was inserted into the cisterna magna through it.…”

“…ACh and Ch concentrations in the CSF samples, CSF dialysates or unprocessed CSF, were determined by a high performance liquid chromatography system with an electrochemical detector (HPLC-ECD: Acetylcholine Analytical System; Eicom Co., Ltd., Kyoto), as previous ly reported (9,10). Briefly, ACh and Ch were separated on an AC-Gel column (medium polarity stylenepolymer, 10 fim particle size, 150 x 6 mm) protected by a guard column (AC-ODS, 5 x 4 mm).…”

“…From a clinical point of view, an estimation of neuro chemical markers in CSF is important for diagnosis and assessment of a cure (3,(6)(7)(8). Because of this, we have reported measurements of CSF neurotransmitters for evaluating the central neuronal activity in anesthetized rats (9,10).…”

“…Significant baseline differences in extracellular concentrations of neurotransmitters and their metabolites were noted following the time course of probe implanta tion. The CSF measurement of neurotransmitters permits the evaluation of the neuronal activity without extensive tissue damage (9,10,30). Thus, in the present study, we applied in vivo microdialysis for measuring the CSF ACh level as a marker of central cholinergic activity in freely moving rats (CSF microdialysis).…”

“…CSF levels of the ACh have rarely been studied because of low concentrations due to the extremely rapid hydrolysis to choline (Ch). Recently, we have reported that central choli nergic function can be evaluated by measuring the CSF levels of ACh in anesthetized rats (9,10,25).…”