T-types make your clock tick.

Abstract

Voltage gated T-type calcium channels are important regulators of rhythmic activity in the mammalian nervous system. T-type channels are ideally suited towards regulating neuronal excitability for several reasons. First, their voltage dependent gating properties generate a ‘window current’ that allows them to become active near typical neuronal resting membrane potentials. Second, their hyperpolarization induced recovery from inactivation kinetics supports rebound burst activity in many types of neurons (Huguenard & Prince, 1994). Finally, these channels associate with, and regulate, the functions of both calcium activated and voltage gated potassium channels, which in turn shape neuronal firing properties (Turner & Zamponi, 2014). Besides regulating neuronal activity, T-type channels also contribute to low threshold exocytosis through physical coupling to the vesicle release machinery (Weiss et al. 2012). All of these aspects of T-type channel function are of direct relevance to an interesting new study by Yu and colleagues (Yu et al. 2015), reported in this issue of The Journal of Physiology, on the role of T-type channels in the pineal gland.