Protection against cerebral hypoxia by local anesthetics: a study using brain slices

The ability of the local anesthetics lidocaine, 2-chloroprocaine and cocaine to protect neuronal tissue against hypoxic damage was evaluated. Rat hippocampal slices were incubated with non-depressive doses of these agents 60 min prior to their exposure to 15 min hypoxia. The rate of recovery of synaptic function (evoked field potentials) following the hypoxic episode was used as an index of hypoxic damage. Slices treated with 0.1 mM of any of the three local anesthetics exhibited a significant increase in the recovery rate of synaptic function from hypoxia as compared to control, untreated slices. These results indicate that local anesthetics, by reducing neuronal sodium influx (and possibly its concomitant calcium influx) which occurs upon hypoxic depolarization, are able to prolong the hypoxic insult a cerebral tissue could tolerate.