The Q-type calcium channel is a type of voltage-dependent calcium channel. Like the others of this class, the α1 subunit is the one that determines most of the channel's properties. They are poorly understood, but like R-type calcium channels, they appear to be present in cerebellar granule cells. They have a high threshold of activation and relatively slow kinetics. External links Ion channels Electrophysiology Membrane biology Integral membrane proteins Calcium channels