Inhibition of the voltage-gated K+ channel Kv1.3 can reduce secondary brain injury after ischaemic stroke, according to a new study published in Annals of Clinical and Translational Neurology. Kv1.3 is upregulated on activated 'M1-like' microglia, which are thought to contribute to inflammatory damage following brain ischaemia and reperfusion. Researchers at the University of California, Davis, USA, tested the small-molecule Kv1.3 inhibitor PAP-1 in mouse and rat models of ischaemic stroke. They found that the drug reduced the size of the infarct and ameliorated neurological deficits in both models. The authors conclude that Kv1.3 inhibition is a promising approach, but it needs to undergo additional testing in models that more closely resemble human stroke before it can enter clinical trials.