When LDH says “open,” channels listen

Achannel that protects cardiac cells from ischemia uses a rapid metabolite detection system to perceive dangerous conditions, according to new results from Russell Crawford, Aleksander Jovanovic, and colleagues (University of Dundee, Dundee, UK).

A heart attack damages cells when anaerobic conditions disrupt active ion transport, leading to a toxic increase in intracellular Ca²⁺. A decrease in ATP levels initially impairs ion transport, causing depolarization and Ca²⁺ import. However, low ATP may also trigger opening of ATP-sensitive K⁺ (K⁺_ATP) channels, which would counteract the depolarization, ultimately reducing the time for Ca²⁺ influx.

But ATP regulation is not the whole story, as K⁺_ATP channels open before intracellular ATP levels drop enough to open the channel. This prompted the group to...