Chunk #41 — 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
Mertens et al.42 reported differential responses to Li depending on whether the neurons were derived from LR or NR patients. To test Li responsiveness in our cells, we chronically treated neurons with 1 mM LiCl (see Materials and methods). Neuronal excitability, as defined by the total evoked action potential, was reduced in neurons from LR patients (59 non-treated cells and 67 treated cells from three cell lines, a reduction of 40% in the total number of evoked spikes in 30 depolarization steps, P = 0.02) but not in neurons from NR patients (44 non-treated cells and 47 treated cells from three cell lines, a reduction of 15% in the total number of evoked action potentials, P = 0.44) upon Li treatment (Figure 6a and i, with representative traces in current clamp mode shown in Figure 6b and j). Representative traces in voltage clamp mode of sodium and potassium currents are shown in Supplementary Figure 3a (LR), 3b (LR Li), 3 h (NR) and 3i (NR Li). The sodium current at −20 mV is shown in the inset of each figure.
