A, Representative traces and B, Mean ± SEM, 3α,5β-THP effects on neuronal excitability recorded from CA1 pyramidal cells (rat) in the hippocampal slice using whole cell recordings in current clamp mode. Membrane voltage was assessed in response to 20 pA increases in current injection. A, Red, current threshold (I-threshold) for action potential (AP) generation for the less excitable group (the recording with the higher current threshold: pre-3α,5β-THP or post-3α,5β-THP). Blue, I-threshold for AP generation for the more excitable group (i.e., the recording with the lower current threshold) before or after bath application of 30 nM 3α,5β-THP. Black, trace(s) in-between the two threshold currents. B, 3α,5β-THP increased Rm (ANOVA, F(3,14)=73, P<0.0001) and lowered I-threshold (ANOVA, F(3,14)=22, P<0.0001) only after 24 h METH Wd, an effect reversed by FLU; n=4-5 rats/group. *P<0.0001 vs. all other groups; n=4-5 rats/group.