Although zinc ion (Zn2+) reduced the low-threshold T-type Ca2+ current of a rat thalamic relay neuron (TRN), we observed that Zn2+ increased a bursting activity of TRN by altering the generation and maintenance of low-threshold spike (LTS). Interestingly and importantly, Zn2+ shifted dramatically the voltage-dependence of both steady-state inactivation and activation of the transient A-type K+ current (IA) to a depolarizing direction. As IA is one of the main factors in shaping thalamic LTS, such alterations of gating properties of IA would contribute to the enhancement of TRN excitability under Zn2+.
Bibliographical noteFunding Information:
This study was supported by Systems Biology Infrastructure Establishment Grant from GIST and a Special Grant from EWU to JMC; Noh, EWU RP-Grant 2009 recipient.