Preconditioning by motor activity protects rat hippocampal CA1 neurons against prolonged ischemia.

Recovery of orthodromic and antidromic population spikes in CA1 hippocampal slices of 30-day-old Wistar rats has been studied in the reperfusion period after prolonged (90 min) decapitation ischemia with and without preceding 15 min long non-voluntary motor activity of intact animals. The preconditioning motor activity significantly enhances the resistance of pyramidal neurons to ischemia at a temperature of 30 degrees C. The period of protection lasts for up to 40 min after the end of motor activity. In case the ischemia was started within 5-10 min after the preconditioning, complete restoration of the field potentials to preischemic control level could be achieved. These data are the first indication of the neuroprotective effect of preconditioning motor activity in CA1 damage after prolonged global ischemia.