Figure 5

Transient application of gold nanoparticles reduces the potassium associated current in CA3 hippocampal neurons. (A) Average action potential before (control) and after application of gold nanoparticles (Au NP). The overlay at this scale makes the traces indistinguishable. (B) The hyperpolarization region of the action potential (from A) is associated with potassium currents. (C) The percent difference in the shaded area integrated from B before and after application of gold nanoparticles for all the experiments (5.0% ± 1.8 S.E.M., n = 8 experiments). (D-F) Computer simulation of action potential generation using the Hodgkin and Huxley model. (D) The model generated sustained firing rates when stimulated with continuous 7 nA. Varying the density of potassium currents (Kdr) by 0.75 results in an increase in firing rate of 17.5%. (E) Action potential overlay comparing the control and 0.75xKdr simulations. (F) Integrating the potassium associated voltage in the model shows a decrease in this current of 4.6%. The shaded area in F covers the same fraction of the action potential as in B.