Effect of stimulation of the nucleus basalis of Meynert on BDNF in the cerebral cortex.

研究了电刺激基底前脑对大脑皮层神经营养因子的影响。在大脑皮层中发现的神经营养因子中，我们重点研究了脑源性神经营养因子（BDNF），它已知对脑缺血具有保护作用。采用氟烷麻醉大鼠顶叶皮层植入神经肽激活探针。细胞外液每100分钟收集一次，持续800分钟。采用酶联免疫吸附法测定各组BDNF的浓度。将刺激电极插入Meynert单侧基底核（NBM），进行200μA、50Hz、1s开/ 2s关的重复电刺激，持续100分钟。假手术大鼠BDNF浓度在整个实验过程中稳定在5pg/ml以下。在nbm刺激的大鼠中，在刺激结束后300-400分钟，皮质灌注液中的BDNF浓度显著增加。本研究结果表明，基底前脑内基底基底基底基底的胆碱能神经纤维被激活后，BDNF在大脑皮层的释放被增强。大脑皮层BDNF释放的增加被认为部分参与了NBM刺激对缺血诱导的延迟神经元死亡的保护作用，我们之前报道过。

The effect of electric stimulation of the basal forebrain on the neurotrophic factors in the cerebral cortex was examined. Among neurotrophines found in the cerebral cortex, we focused on brain-derived neurotrophic factor (BDNF) that it known to have a protective action against cerebral ischemia. A neuropeptide dyalisis probe was implanted in the cerebral cortex of parietal lobe using halothane-anesthetized rats. Extracellular fluid was collected every 100 minutes, for 800 minutes. Concentration of BDNF in the collected samples was measured by ELISA. Stimulating electrode was inserted into the unilateral nucleus basalis of Meynert (NBM), and repetitive electric stimulation (200μA, 50Hz and 1s on/ 2s off) was performed for 100 minutes. In sham-operated rats, BDNF concentration was stable at a level less than 5pg/ml throughout experiment. In NBM-stimulated rats, BDNF concentration in the cortical perfusate increased significantly at 300-400 minutes after the end of stimulation. The present result suggests that release of BDNF in the cerebral cortex was enhanced by activation of the cholinergic nerve fibers originating in the NBM in the basal forebrain and projecting to the cerebral cortex. The increase in BDNF release in the cerebral cortex is suggested to be partly involved in the protective action of NBM stimulation against ischemia-induced delayed neuronal death that we have reported previously.