Author response image 3. Voltage-dependency of the nicotinic calcium.
(A) Nicotinic I/V relationship with iohophoretic ACh applications in media for which the Ca2+ ion only carries the nicotinic current. Na+ and Mg2+ were removed, K+ was adjusted for each holding potential in order to remain at the equilibrium, and Lysine hydrochloride was inversely adjusted to KCl in order to hold both the osmotic pressure and the ionophoretic ACh application. Dashed line shows the rectification predicted with the GHK free diffusion model. (B) Example for a given cell surface of simulation of the nicotinic calcium in V- and I-clamp. The model comprised a synapse, a linear passive K+ leak, an inward rectifying K+ leak, two voltage-gated K+ conductances and a voltage-gated Na+ conductance.