Figure 8.

AP clamp reveals differential activation of Nav1.5 and Nav1.9 during AP. Myenteric neurons expressing either I_NaP and I_NaT (red trace) or only I_NaT (blue trace). Neurons were subjected to the AP voltage command for recording of spike-elicited sodium currents. A substantial fraction of I_NaP (Nav1.9) was activated during membrane repolarization, whereas I_NaT (Nav1.5) flowed essentially during the upstroke. Note that all inward currents were abolished by iso-osmotic substitution of Na⁺ by sucrose ([Na⁺]_o = 0, black trace).