Tim Ziebarth

Abstract Genetically encoded calcium (Ca2+) indicators (GECIs) are essential tools for monitoring neuronal activity, but the performance of red fluorescent GECIs has remained limited. In particular, many red indicators are relatively dim, produce low signal-to-noise ratios and can undergo unwanted photoswitching when exposed to blue light, restricting their use in all-optical experiments that combine imaging with optogenetics or multicolor imaging.

Abstract Norepinephrine (NE) is a critical neuromodulator that dynamically shapes brain states and behavior. Genetically encoded fluorescent NE indicators have enabled in vivo visualization of NE release, yet their limited sensitivity and spectral flexibility constrain widespread use in complex experimental paradigms. Here we developed next-generation green and red fluorescent NE indicators, named nLightG2 and nLightR2, respectively.

Abstract Neural glutamate homeostasis plays a key role in health and disease. In ischemic conditions, such as stroke, this homeostasis is severely disrupted since energy depletion and ion imbalances lead to more glutamate release and less uptake. We here used the fluorescent glutamate sensor SF iGluSnFR(A184V) to probe the effects of chemical ischemia on extracellular glutamate dynamics in situ, using organotypic slice cultures from mouse cortex.