Analysis of ischemic neuronal injury in Cav2.1 channel α1 subunit mutant mice.

One of the main instigators leading to cell death and brain damage following ischemia is Ca(2+) dysregulation. Neuronal membrane depolarization results in the activation of voltage-gated Ca(2+) (CaV) channels and intracellular Ca(2+) influx. We investigated the physiological role of the CaV2.1 (P/Q-type) channel in ischemic neuronal injury using CaV2.1 channel α1 subunit mutant mice, rolling Nagoya and leaner mice. The in vivo ischemia model with a complete occlusion of the middle cerebral artery showed that the infarct area at 24h was significantly smaller in rolling Nagoya (27.1±3.5% of total brain volume) and leaner (20.1±3.5%) mice compared to wild-type (42.9±4.5%) mice. In an in vitro Ca(2+) imaging study, oxygen-glucose deprivation using a hippocampal slice induced a significantly slower rate of increase in intracellular Ca(2+) concentration ([Ca(2+)]i) in rolling Nagoya (0.083±0.007/min) and leaner (0.062±0.006/min) mice compared to wild-type (0.105±0.008/min) mice. These results demonstrate that the mutant CaV2.1 channel in rolling Nagoya and leaner mice plays a different protective role in a ([Ca(2+)]i)-dependent manner in ischemic models and indicate that CaV2.1 channel blockers may be used preventively against ischemic injury.