Influence of ischemia on spike encoding at cerebellar Purkenje cells in rats

Objective: To study the changes of the intrinsic electrophysiological characteristics of cerebellar Purkinje cells and the possible mechanisms during the early stage of simulated ischemia by reducing the perfusion to the sagittal slices of cerebellar vermis in rat.Methods: The sagittal slices of cerebellar vermis(400 μm) were prepared.The recordings of threshold potentials of firing spikes and refractory periods following each spike of simulated ischemia cells were conducted in a whole-cell model with an Axoclamp-2B amplifier;and the electrical signals were input into pClamp 9.2 for data acquisition,analysis of inter-spike interval and standard deviation of spike timing,in order to detect the changes in the intrinsic electrophysiological properties at Purkinje neurons during the simulated ischemia.Results: Shortly after reducing the perfusion rate,refractory periods of sequential spikes were shortened and the threshold potentials of firing spikes lowered(P<0.01).Conclusions: The ischemia changes the refractory periods and the threshold potentials of sequential spikes,which causes over-excitation of cerebellar Purkinje cells and deteriorates spike encoding at cerebellar Purkinje cells.