Recovery from Inactivation of T-Type Ca2+ Channels in Rat Thalamic Neurons

摘要: We studied the gating kinetics, especially kinetics of recovery from inactivation, T-type Ca 2+ channels (T-channels) in thalamic neurons. The course is associated with no discernible current and characterized by an initial delay, as well a subsequent exponential phase. These findings are qualitatively similar to previous observations on neuronal Na + suggest that T-channels also must deactivate recover inactivation. In contrast which both delay time constant phase shortened increasing hyperpolarization, remains unchanged between −100 −200 mV, although still e -fold per 43 mV hyperpolarization over same voltage range. deactivating tail T-currents show dependence −90 −170 mV. According hinged-lid model fast these affinity difference inactivating peptide binding activated channel fully deactivated much smaller than channels. Moreover, seems have slower unbinding rates probably remain once inactivated T-channel has gone through steps deactivation “closes” pore (with activation gate). thus might more rigid hinge abrupt conformational change inactivation machinery opening closing pore.