Metea Monica R, Newman Eric A
Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA.
J Neurosci. 2006 Mar 15;26(11):2862-70. doi: 10.1523/JNEUROSCI.4048-05.2006.
Neuronal activity evokes localized changes in blood flow. Although this response, termed neurovascular coupling, is widely used to monitor human brain function and diagnose pathology, the cellular mechanisms that mediate the response remain unclear. We investigated the contribution of glial cells to neurovascular coupling in the acutely isolated mammalian retina. We found that light stimulation and glial cell stimulation can both evoke dilation or constriction of arterioles. Light-evoked and glial-evoked vasodilations were blocked by inhibitors of cytochrome P450 epoxygenase, the synthetic enzyme for epoxyeicosatrienoic acids. Vasoconstrictions, in contrast, were blocked by an inhibitor of omega-hydroxylase, which synthesizes 20-hydroxyeicosatetraenoic acid. Nitric oxide influenced whether vasodilations or vasoconstrictions were produced in response to light and glial stimulation. Light-evoked vasoactivity was blocked when neuron-to-glia signaling was interrupted by a purinergic antagonist. These results indicate that glial cells contribute to neurovascular coupling and suggest that regulation of blood flow may involve both vasodilating and vasoconstricting components.
神经元活动会引起局部血流变化。尽管这种被称为神经血管耦合的反应被广泛用于监测人类脑功能和诊断病理状况，但其介导该反应的细胞机制仍不清楚。我们研究了胶质细胞在急性分离的哺乳动物视网膜神经血管耦合中的作用。我们发现光刺激和胶质细胞刺激都能引起小动脉的扩张或收缩。光诱发和胶质细胞诱发的血管舒张被细胞色素P450环氧合酶（一种环氧二十碳三烯酸的合成酶）抑制剂所阻断。相反，血管收缩被ω-羟化酶抑制剂所阻断，该酶可合成20-羟基二十碳四烯酸。一氧化氮影响了对光和胶质细胞刺激所产生的血管舒张或收缩。当神经元与胶质细胞的信号传导被嘌呤能拮抗剂中断时，光诱发的血管活性被阻断。这些结果表明胶质细胞对神经血管耦合有贡献，并提示血流调节可能涉及血管舒张和血管收缩成分。
