Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, WBSB 1001, Baltimore, MD 21205, USA.
Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, WBSB 1001, Baltimore, MD 21205, USA.
Neuron. 2014 Jun 18;82(6):1263-70. doi: 10.1016/j.neuron.2014.04.038.
Astrocytes perform crucial supportive functions, including neurotransmitter clearance, ion buffering, and metabolite delivery. They can also influence blood flow and neuronal activity by releasing gliotransmitters in response to intracellular Ca(2+) transients. However, little is known about how astrocytes are engaged during different behaviors in vivo. Here we demonstrate that norepinephrine primes astrocytes to detect changes in cortical network activity. We show in mice that locomotion triggers simultaneous activation of astrocyte networks in multiple brain regions. This global stimulation of astrocytes was inhibited by alpha-adrenoceptor antagonists and abolished by depletion of norepinephrine from the brain. Although astrocytes in visual cortex of awake mice were rarely engaged when neurons were activated by light stimulation alone, pairing norepinephrine release with light stimulation markedly enhanced astrocyte Ca(2+) signaling. Our findings indicate that norepinephrine shifts the gain of astrocyte networks according to behavioral state, enabling astrocytes to respond to local changes in neuronal activity.
星形胶质细胞发挥着至关重要的支持功能，包括神经递质清除、离子缓冲和代谢物输送。它们还可以通过响应细胞内 Ca(2+) 瞬变释放神经胶质递质来影响血流和神经元活动。然而，对于星形胶质细胞在体内不同行为期间如何参与，我们知之甚少。在这里，我们证明去甲肾上腺素使星形胶质细胞能够检测皮质网络活动的变化。我们在小鼠中表明，运动触发了多个脑区星形胶质细胞网络的同时激活。这种对星形胶质细胞的全局刺激被 α-肾上腺素受体拮抗剂抑制，并通过从大脑中去除去甲肾上腺素而消除。尽管在单独用光刺激激活神经元时，清醒小鼠视觉皮层中的星形胶质细胞很少被激活，但将去甲肾上腺素的释放与光刺激结合可以显著增强星形胶质细胞 Ca(2+) 信号。我们的发现表明，去甲肾上腺素根据行为状态调整星形胶质细胞网络的增益，使星形胶质细胞能够对神经元活动的局部变化做出反应。
