CaMKIIα knockout protects from ischemic neuronal cell death after resuscitation from cardiac arrest.

CaMKIIα plays a dual role in synaptic plasticity, as it can mediate synaptic changes in opposing directions. We hypothesized that CaMKIIα plays a similar dual role also in neuronal cell death and survival. Indeed, the CaMKII inhibitor tatCN21 is neuroprotective when added during or after excitotoxic/ischemic insults, but was described to cause sensitization when applied long-term prior to such insult. However, when comparing long-term CaMKII inhibition by several different inhibitors in neuronal cultures, we did not detect any sensitization. Likewise, in a mouse in vivo model of global cerebral ischemia (cardiac arrest followed by cardiopulmonary resuscitation), complete knockout of the neuronal CaMKIIα isoform did not cause sensitization but instead significant neuroprotection.