A small-conductance Ca2+-dependent K+ current regulates dopamine neuron activity: a combined approach of dynamic current clamping and intracellular imaging of calcium signals

To analyze the small-conductance calcium-dependent K+ current observed in dopaminergic neurons of the rat midbrain, we have developed a new dynamic current clamping method that incorporates recording of intracellular Ca2+ levels. As reported earlier, blocking the small-conductance current with apamin shifted the firing modes of dopaminergic neurons and changed the firing rate and spike afterhyperpolarization. We modeled the kinetic properties of the current and assessed the model in a real-time computational system. Here, we show that the spike afterhyperpolarization is regulated by the small-conductance current, an effect that is observed in dopaminergic neurons. Thus, this current can effectively shape the autonomous firing patterns of dopaminergic neurons.