<p>Nature Chemical Biology, Published online: 03 March 2026; <a href="https://www.nature.com/articles/s41589-026-02159-4">doi:10.1038/s41589-026-02159-4</a></p>We used DNA nanostructures to develop nanotraps for the rapid and selective imaging and quantification of norepinephrine (NE) dynamics in subcellular organelles. Using these nanoprobes, we discovered NE bursts in the endoplasmic reticulum (ER) during traumatic brain injury. Increased NE levels in the ER were associated with ER stress, mitochondrial dysfunction and neuronal death.