Cerebellar slice cultures from mice lacking the P/Q calcium channel: electroresponsiveness of Purkinje cells

Abstract To investigate the role of P/Q type Ca 2+ channels in determining the firing pattern of Purkinje cells (PCs) we compared the somatically evoked discharge of action potentials (APs) in PCs from 3 to 4 week old cerebellar slice cultures obtained with ataxic mice lacking α 1A -subunit (α −/− ) and with normal mice (non-ataxic α +/− or α +/+ ) using the whole-cell configuration of the patch-clamp recording method. Whereas evoked responses of PCs in normal mice were mainly fast APs, those of PCs from ataxic mice were mainly low-threshold Ca 2+ spikes (LTS). Furthermore, a sustained plateau potential due to the activation of cadmium sensitive Ca 2+ conductances was not observed in PCs from ataxic mice by blocking K + channels. These results confirm that P/Q Ca 2+ channels elicit Ca 2+ -dependent plateau potentials and control the propagation of the dendritic LTS to the soma.