Chunk #44 — RESULTS — Hyperexcitability is reversed by chronic Li treatment of LR DG-like neurons but not of NR neurons, and Li treatment reduces cell capacitance in both LR and NR neurons
P = 0.03), with an effect in the same direction in NR neurons (Supplementary Figures 3e and l), and the threshold for firing decreased in the NR neurons (3 mV less depolarized, P = 0.04) with an effect in the same direction in LR neurons (Supplementary Figures 3f and m). The input conductance did not change for either cell type (Supplementary Figures 3g and n). Interestingly, the effect of Li on both LR and NR neurons is similar, but the final effect depends on the cell’s initial properties. Therefore, Li acts in two different ways: on the one hand, it decreases fast AHP amplitude and broadens the spike; on the other hand, it reduces the threshold for evoking an action potential and increases the sodium currents around −40 mV. This dual form of action might be the mechanism that allows Li to improve symptoms in both mania and depression phases. The final significance of the effect of Li depends on the original properties of the cells. For example, LR spikes are very narrow, and after Li treatment they become significantly broader, whereas NR spikes are broad to begin with and become broader with Li, but not significantly. While the final
