Voltage-dependent calcium currents in Purkinje cells from rat cerebellar vermis.

Whole-cell patch clamp recording was used to characterize calcium currents in Purkinje cells dissociated from the cerebellar vermis of 1-3-week postnatal rats. A subset of Purkinje cells had a low-threshold, transient current similar to the T-type current in peripheral neurons. All Purkinje cells had a high-threshold, slowly inactivating current. Only a small component of the high-threshold current was sensitive to dihydropyridine (DHP) antagonists or to the dihydropyridine agonist BAY K8644. omega-Conotoxin had very little effect on the high-threshold current. The results suggest that these Purkinje cells have at least three types of calcium channels: T-type channels (present in only a fraction of cells), DHP-sensitive L-type channels (contributing a small fraction of the high-threshold current), and a predominant type of high-threshold channel that is pharmacologically distinct from L-type and N-type channels characterized in peripheral neurons.