Fig. 2.

Neurons from the night period display membrane depolarization and reduced conductance. A: graphs depict the significantly more depolarized resting membrane potential (RMP; left) and lower resting conductance (right) in aPVT neurons recorded from slices prepared during the night period (ZT 14–18; n = 73) vs. the day period (ZT 2–6; n = 144). Data are means ± SE for both axes. B: graphs are cumulative plots for RMP (left) and conductance (right) for all aPVT neurons included in Fig. 1, from both ZT periods. Statistical comparisons were performed using the Kolmogorov-Smirnov (KS) test. C: graph of the averaged (mean ± SE) current-voltage (I-V) relationships for all cells reveals a difference between data from neurons recorded in slices prepared during each ZT period. The net difference current (gray plot) calculated by subtraction (data from day period minus data from night period) reflects the reduction in membrane conductance recorded in neurons from the night period, with a net reversal potential approximating −110 mV. D: plots of the RMPs vs. resting conductances for neurons recorded from the day period (red; left) and night period (black; right). The gray lines, representing linear regressions, reveal a significant correlation only in the data from neurons prepared during the day period (Pearson correlation test; P = 0.008).