Figure 7.

Analysis of positive feedback between TRPV4 and K_Ca channels in PVN neurones. (A) The simple scheme proposed by Nilius and Droogmans (2001) whereby influx of Ca²⁺ increases K_Ca channel activity which hyperpolarizes the cell and increases the inward flux of Ca²⁺, by increasing the driving force (G [Vm – E_Ca]) for Ca²⁺ entry. (Vm = membrane potential, E_Ca is the equilibrium potential for Ca²⁺ ions and G is the conductance of the Ca²⁺ entry pathway). (B) Running a number of simulations reveals a significant decrease (n = 7; *P < 0.001) in mean Ca²⁺ influx in the presence of K_Ca channels, as predicted. See Figure 6 for experimental verification.