Preliminary Model: I-NaP and I-KM sensitivity
As reported by D’Angelo et al. (2001), the bursting response of this model cell under constant current injection was exquisitely sensitive to a balance between the slow, noninactivating I-NaP and I-KM conductances. The burst was eliminated by either a 7% decrease in I-NaP gnabar or a 5% increase in I-KM gkbar (figures 5b-i, 5c-iii). Modifying these maximum conductances in their respective opposite directions had identical effects of decreasing latency to burst onset and decreasing burst length and spike number. This attenuation was due to saturating depolarization in both cases, i.e. gradual inactivation of I-NaF channels following each of the first several spikes in the burst. The fact that the burst properties of the model cell are extremely sensitive to the balance between these two conductances, as seen in these preliminary tests, made clear the necessity of more extensive, multidimensional parameter space tests for the model when placed under more realistic input conditions.
