基底前脑刺激对梨状皮质区域血流及细胞外乙酰胆碱释放的影响。

文献信息

中文摘要

引言： 梨状皮质接受来自基底前脑内斜角带水平支（HDB）神经元的丰富胆碱能支配。本研究探讨化学刺激HDB是否增加梨状皮质区域血流和细胞外乙酰胆碱（ACh）水平，以及诱发的血流动力学反应是否依赖于胆碱能受体激活。
方法： 实验在15只成年雄性Fischer 344大鼠上进行。在麻醉下，使用激光多普勒血流仪测量梨状皮质区域血流。通过微透析结合高效液相色谱和电化学检测（HPLC-ECD）测定该处细胞外ACh浓度。通过微量注射L-谷氨酸（50-100 nmol）对单侧HDB进行局部化学刺激。
结果： 以50和100 nmol剂量的L-谷氨酸刺激HDB后，同侧梨状皮质区域血流分别增加至刺激前基线水平的约112%和127%。HDB刺激对平均动脉压无显著影响。在静脉预先给予胆碱能受体拮抗剂阿托品和美加明的大鼠中，HDB刺激未改变梨状皮质血流。HDB刺激还增加了同侧梨状皮质细胞外ACh浓度。
结论： 本研究表明，刺激基底前脑HDB神经元可增加梨状皮质区域血流，并伴随同一区域ACh释放增加，且胆碱能受体阻断可消除这种血流反应。该区域胆碱能输入受损可能破坏血流动力学调节，导致嗅觉功能障碍。

英文摘要

INTRODUCTION: The piriform cortex receives substantial cholinergic innervation from neurons in the horizontal limb of the diagonal band of Broca (HDB) within the basal forebrain. This study investigated whether chemical stimulation of the HDB increases regional blood flow and extracellular acetylcholine (ACh) levels in the piriform cortex and whether the evoked hemodynamic response depends on cholinergic receptor activation.
METHODS: The experiments were performed on 15 adult male Fischer 344 rats. Under anesthesia, regional blood flow in the piriform cortex was measured using laser Doppler flowmetry. Extracellular ACh concentrations there were determined using microdialysis coupled with high-performance liquid chromatography and electrochemical detection (HPLC-ECD). Focal chemical stimulation of unilateral HDB was performed by microinjection of L-glutamate (50-100 nmol).
RESULTS: Following HDB stimulation with L-glutamate at doses of 50 and 100 nmol, regional blood flow in the ipsilateral piriform cortex increased to approximately 112% and 127% of prestimulus baseline levels, respectively. Mean arterial pressure was not significantly affected by HDB stimulation. In rats pretreated intravenously with the cholinergic receptor antagonists atropine and mecamylamine, HDB stimulation did not alter blood flow in the piriform cortex. HDB stimulation also increased extracellular ACh concentrations in the ipsilateral piriform cortex.
CONCLUSION: This study showed that stimulation of HDB neurons in the basal forebrain increases regional blood flow in the piriform cortex, accompanied by an increase in ACh release in the same region, and that cholinergic receptor blockade abolishes this blood flow response. Impaired cholinergic input in this region may disrupt hemodynamic regulation, leading to olfactory dysfunction.