[Optical recording method for evaluation of neuronal damage in rat hippocampal slices during ischemia and...

OBJECTIVE: To develop a novel technique of optical recording and its validation for assessment of the neuroprotective effect of nimodipine, a L-type calcium channel blocker. METHODS: In vitro ischemia was induced by oxygen/glucose deprivation (OGD), the light transmittance (LT) of rat hippocampal slices undergoing OGD and reperfusion was quantitated using a simple apparatus relying on basic principles of light transmittance and a computerised image analysis system. RESULTS: OGD was associated with increased LT in the stratum radiatum of CA1 area and the dentate gyrus in hippocampal slices. Peak LT occurred (7.59 +/-1.42) min after OGD, followed by a marked decrease in LT (n=15 slices). Nimodipine administration (0.5 &mgr;mol/L, n=10 slices, 5 &mgr;mol/L, n=9 slices) appeared to protect the tissue from OGD damage by inhibiting elevation of LT, However, 50 &mgr;mol/L nimodipine resulted in increased LT (25.83 +/-6.32). min after administration (n=11 slices). CONCLUSION: LT signal measurement is a non-invasive, reliable method for determination of neuronal damage in ischemic rat brain slices Nimodipine is demonstrated opposite neuroprotective effects depending on its dose.