Kalén P, Kokaia M, Lindvall O, Björklund A
Department of Medical Cell Research, University of Lund, Sweden.
Brain Res. 1988 Dec 6;474(2):374-9. doi: 10.1016/0006-8993(88)90454-4.
Extracellular levels of noradrenaline (NA) were measured in the hippocampus of awake and halothane-anaesthetized rats, using intracerebral dialysis coupled to a highly sensitive radioenzymatic assay. In awake animals, steady state NA output after 1 h of perfusion was 69 +/- 21 fmol/30 microliter (15 min). Non-noxious sensory stimulation increased the steady state NA output by 35%, while halothane anaesthesia reduced the levels by 63-72%. During halothane anaesthesia KCl (100 mM) or desipramine (5 microM) added to the perfusion medium increased the NA levels 27-fold and 8-fold, respectively. Tetrodotoxin added in the presence of desipramine reduced the extracellular NA levels by 85%. In 6-OHDA lesioned animals the NA levels were below the limit of detection in virtually all samples (i.e. less than 3 fmol/30 microliter) at 10-16 days after lesion, but there was a partial recovery at longer postoperative time points. These results support the conclusion that the extracellular NA levels recovered in the dialysis perfusates are neuronally derived and can be used as an index of noradrenergic synaptic activity in the brain.
采用脑内透析结合高灵敏度放射酶分析法，测定清醒和氟烷麻醉大鼠海马中的去甲肾上腺素（NA）细胞外水平。在清醒动物中，灌注1小时后的稳态NA输出为69±21飞摩尔/30微升（15分钟）。无害的感觉刺激使稳态NA输出增加35%，而氟烷麻醉使水平降低63 - 72%。在氟烷麻醉期间，向灌注介质中添加氯化钾（100毫摩尔）或地昔帕明（5微摩尔）可使NA水平分别增加27倍和8倍。在存在地昔帕明的情况下添加河豚毒素可使细胞外NA水平降低85%。在6 - 羟基多巴胺损伤的动物中，损伤后10 - 16天几乎所有样本中的NA水平均低于检测限（即低于3飞摩尔/30微升），但在术后较长时间点有部分恢复。这些结果支持以下结论：透析灌流液中恢复的细胞外NA水平源自神经元，可作为大脑中去甲肾上腺素能突触活动的指标。
