Activators of ATP-sensitive K+ channels reduce anoxic depolarization in CA3 hippocampal neurons.

In CA3 hippocampal neurons of the rat, brief anoxic episodes produce a depolarization which is probably due to a synaptic release of glutamate. Diazoxide, an activator of ATP-sensitive K+ channels (K+ ATP), blocks the anoxic depolarization and has no effect in control oxygenated artificial cerebrospinal fluid. The hormone somatostatin which activates K+ ATP channels in the pancreas also reduces the anoxic depolarization in CA3 neurons. We suggest that drugs that open K+ ATP channels may constitute a novel approach to selectivity reducing the deleterious effects of excessive release of glutamate during anoxia without producing a generalized blockade of glutamatergic synaptic transmission.