Herman Peter, Sanggaard Simon, James Shaun D, Akif Adil, Mishra Sandeep Kumar, Sanganahalli Basavaraju G, Verhagen Justus V, Blumenfeld Hal, Hyder Fahmeed
Department of Radiology and Biomedical Imaging, Yale University, 300 Cedar Street, New Haven, CT 06520, United States.
Magnetic Resonance Research Center, Yale University, 300 Cedar Street, New Haven, CT 06520, United States.
Cereb Cortex. 2025 Jul 1;35(7). doi: 10.1093/cercor/bhaf165.
Neurovascular coupling links calcium (Ca2+)-dependent neuronal activity to cerebral blood volume changes, whereas neurometabolic coupling describes alterations of neuronal activity and glucose uptake. While mesoscale optical imaging of neurovascular coupling is prevalent, neurometabolic coupling has been explored much less. We describe a multiplexed optical system with a closed cranial window setup for longitudinal studies in Thy1-jRGECO1a mice where neuronal activity is measured with Ca2+-dependent red fluorescence, glucose uptake with bolus injections of 2NBDG with green fluorescence, and cerebral blood volume (CBV) with near-infrared spectroscopy (NIRS). Genetically encoded calcium indicators (GECIs) provide strong fluorescent signals for assessing Ca2+-dependent neuronal activity. Thy1-jRGECO1a, a novel GECI with red fluorescence emission that penetrates deeper into tissue, allows for simultaneous imaging of metabolic activity using a green-fluorescent glucose analog, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2NBDG), which is taken up like glucose and then phosphorylated. Dual-fluorescent (red, green) and NIRS recordings confirm strong neurovascular coupling during hindpaw stimuli (Ca2+-CBV; P = 0.0033, r2 = 0.91), whereas neurometabolic coupling (Ca2+-2NBDG; P < 0.001) was three times stronger during stimulation (r2 = 0.75; slope = 0.6) compared to rest (r2 = 0.49; slope = 0.23). In summary, multiplexed optical imaging can be used to reveal mechanisms of neurovascular and neurometabolic (un)couplings during ischemia, traumatic brain injury, aging, and Alzheimer's disease.
神经血管耦合将钙（Ca2+）依赖性神经元活动与脑血容量变化联系起来，而神经代谢耦合则描述了神经元活动和葡萄糖摄取的改变。虽然神经血管耦合的中尺度光学成像很普遍，但对神经代谢耦合的研究要少得多。我们描述了一种具有封闭颅窗设置的多路复用光学系统，用于在Thy1-jRGECO1a小鼠中进行纵向研究，其中通过Ca2+依赖性红色荧光测量神经元活动，通过静脉注射具有绿色荧光的2NBDG测量葡萄糖摄取，并通过近红外光谱（NIRS）测量脑血容量（CBV）。基因编码钙指示剂（GECIs）为评估Ca2+依赖性神经元活动提供了强烈的荧光信号。Thy1-jRGECO1a是一种新型的具有红色荧光发射的GECI，其能更深入地穿透组织，允许使用绿色荧光葡萄糖类似物2-（N-（7-硝基苯并-2-恶唑-1,3-二氮杂环丁烷-4-基）氨基）-2-脱氧葡萄糖（2NBDG）同时成像代谢活动，2NBDG的摄取方式与葡萄糖相同，然后被磷酸化。双荧光（红色、绿色）和NIRS记录证实，在后爪刺激期间存在强烈的神经血管耦合（Ca2+-CBV；P = 0.0033，r2 = 0.91），而与静息状态（r2 = 0.49；斜率 = 0.23）相比，刺激期间神经代谢耦合（Ca2+-2NBDG；P < 0.001）要强三倍（r2 = 0.75；斜率 = 0.6）。总之，多路复用光学成像可用于揭示缺血、创伤性脑损伤、衰老和阿尔茨海默病期间神经血管和神经代谢（解）耦合的机制。
