Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA.
National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20857, USA.
Mol Psychiatry. 2024 Mar;29(3):820-834. doi: 10.1038/s41380-023-02373-9. Epub 2024 Jan 19.
Cocaine affects both cerebral blood vessels and neuronal activity in brain. Cocaine can also disrupt astrocytes, which modulate neurovascular coupling-a process that regulates cerebral hemodynamics in response to neuronal activation. However, separating neuronal and astrocytic effects from cocaine's direct vasoactive effects has been challenging, partially due to limitations of neuroimaging techniques able to differentiate vascular from neuronal and glial effects at high temporal and spatial resolutions. Here, we used a newly-developed multi-channel fluorescence and optical coherence Doppler microscope (fl-ODM) that allows for simultaneous measurements of neuronal and astrocytic activities (reflected by the intracellular calcium changes in neurons Ca and astrocytes Ca, respectively) alongside their vascular interactions in vivo to address this challenge. Using green and red genetically-encoded Ca indicators differentially expressed in astrocytes and neurons, fl-ODM enabled concomitant imaging of large-scale astrocytic and neuronal Ca fluorescence and 3D cerebral blood flow velocity (CBFv) in vascular networks in the mouse cortex. We assessed cocaine's effects in the prefrontal cortex (PFC) and found that the CBFv changes triggered by cocaine were temporally correlated with astrocytic Ca activity. Chemogenetic inhibition of astrocytes during the baseline state resulted in blood vessel dilation and CBFv increases but did not affect neuronal activity, suggesting modulation of spontaneous blood vessel's vascular tone by astrocytes. Chemogenetic inhibition of astrocytes during a cocaine challenge prevented its vasoconstricting effects alongside the CBFv decreases, but it also attenuated the neuronal Ca increases triggered by cocaine. These results document a role of astrocytes both in regulating vascular tone and consequently blood flow, at baseline and for modulating the vasoconstricting and neuronal activation responses to cocaine in the PFC. Strategies to inhibit astrocytic activity could offer promise for ameliorating vascular and neuronal toxicity from cocaine misuse.
可卡因会影响大脑中的脑血管和神经元活动。可卡因还可以破坏星形胶质细胞，星形胶质细胞调节神经血管耦联——这是一种调节大脑血液动力学以响应神经元激活的过程。然而，将可卡因的直接血管活性作用与神经元和星形胶质细胞的作用分开一直具有挑战性，部分原因是神经影像学技术的局限性，这些技术能够以高时空分辨率区分血管、神经元和神经胶质的作用。在这里，我们使用了一种新开发的多通道荧光和光相干多普勒显微镜 (fl-ODM)，该显微镜允许同时测量神经元和星形胶质细胞的活动（分别反映神经元中的细胞内钙变化 Ca 和星形胶质细胞中的 Ca），以及它们在体内的血管相互作用，以解决这一挑战。使用在星形胶质细胞和神经元中差异表达的绿色和红色基因编码 Ca 指示剂，fl-ODM 能够同时对大脑皮层血管网络中的大尺度星形胶质细胞和神经元 Ca 荧光和 3D 脑血流速度 (CBFv) 进行成像。我们评估了可卡因在前额叶皮层 (PFC) 中的作用，发现可卡因引起的 CBFv 变化与星形胶质细胞 Ca 活性具有时间相关性。在基线状态下化学遗传抑制星形胶质细胞会导致血管扩张和 CBFv 增加，但不会影响神经元活动，这表明星形胶质细胞调节自发血管的血管张力。在可卡因挑战期间化学遗传抑制星形胶质细胞可防止其血管收缩作用以及 CBFv 降低，但也会减弱可卡因引发的神经元 Ca 增加。这些结果证明了星形胶质细胞在调节血管张力以及在 PFC 中调节血管收缩和神经元对可卡因激活的反应方面的作用。抑制星形胶质细胞活性的策略可能有望改善可卡因滥用引起的血管和神经元毒性。
