Cerebellar Purkinje cells: membrane property changes on partial deafferentation.

The responses of the cerebellar Purkinje cell to removal of its climbing fiber input has been studied electrophysiologically in slices of rat cerebella. Using single electrode current clamp methods, membrane potentials were recorded in various conditions from normal and 3-AP deafferented Purkinje cells (PC). The membrane of the deafferented PC showed a rectification for hyperpolarizing currents which varied in degree with length of time after removal of the climbing fiber input. While this rectification was the most pronounced change in membrane properties provoked by the deafferentation, other more subtle effects were observed in experiments with changes in extracellular ionic compositions. Since the rectification began at membrane potentials near -60 mV, it could prevent membrane hyperpolarization by inhibitory synaptic inputs and thus produce an apparent hypersensitivity to excitatory inputs.