ERG current in repolarizing plateau potentials in dopamine neurons (Canavier et al 2007)


"Blocking the small-conductance (SK) calcium-activated potassium channel promotes burst firing in dopamine neurons both in vivo and in vitro. ... We focus on the underlying plateau potential oscillation generated in the presence of both apamin and TTX, so that action potentials are not considered. We find that although the plateau potentials are mediated by a voltage-gated Ca2+ current, they do not depend on the accumulation of cytosolic Ca2+, then use a computational model to test the hypothesis that the slowly voltage-activated ether-a-go-go–related gene (ERG) potassium current repolarizes the plateaus. The model, which includes a material balance on calcium, is able to reproduce the time course of both membrane potential and somatic calcium concentration, and can also mimic the induction of plateau potentials by the calcium chelator BAPTA." See paper for more.

Model Type: Neuron or other electrically excitable cell

Cell Type(s): Substantia nigra pars compacta DA cell

Currents: I L high threshold; I h; I K,Ca; I Calcium; I_HERG

Model Concept(s): Ion Channel Kinetics; Oscillations; Calcium dynamics

Simulation Environment: C or C++ program; FORTRAN

Implementer(s): Canavier, CC

References:

Canavier CC, Oprisan SA, Callaway JC, Ji H, Shepard PD. (2007). Computational model predicts a role for ERG current in repolarizing plateau potentials in dopamine neurons: implications for modulation of neuronal activity. J Neurophysiol 98 [PubMed]