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. Author manuscript; available in PMC: 2011 Jun 15.
Published in final edited form as: Biol Psychiatry. 2010 Apr 8;67(12):1128–1136. doi: 10.1016/j.biopsych.2010.02.008

Figure 2. Chronic stress increased the excitability of LAT neurons.

Figure 2

A) Repeated restraint stress increased excitability measured from the neuronal resting membrane potential (Vrest; mixed design repeated measures ANOVA of each stimulation intensity, main effect of stimulation intensity F(5,264) = 31.67, p<0.001; main effect of stress F(1, 264) = 47.12, p<0.001; interaction F(5, 264) = 8.19, p<0.001). Shown here are voltage traces at the resting membrane potential of a neuron from the chronic handling control (left, Vrest = −79 m V; black circle in plot) and the chronic stress (right, Vrest = −72 m V, white circle in plot), in response to the same amplitude of current injection. B) The effect of chronic stress on excitability was only observed after repeated restraint, and not after a single restraint session (mixed design repeated measures ANOVA of each stimulation intensity, main effect of stress F(1, 72) = 0.79, p=0.376; main effect of stimulation intensity F(5,72) = 24.02, p<0.001; interaction F(5,72) = 0.20, p=0.96). This is measured as the response of these neurons to a depolarizing steps (squares in plot, one day control, black; one day stress, white). C) Repeated restraint stress caused an increase of LAT neuronal excitability when the membrane potential was held near −70 m V (mixed design repeated measures ANOVA of each stimulation intensity, main effect of stress F(1,264) = 22.19, p<0.001; main effect of stimulation intensity F(5,264) = 34.55, p<0.001; interaction F(5,264) = 3.39, p=0.005, * indicates p<0.05 between control and stress group in post-hoc unpaired t-tests with Bonferroni corrections). D) The effects of chronic stress on excitability were still observed when DNDS was included in the recording pipette (mixed design repeated measures ANOVA, main effect of stress F(1, 126) = 18.93, p<0.001, main effect of stimulation intensity F(5,126) = 47.59, p<0.001; control 0.88 ± 0.09 AP/ 100 pA, n=12; stress 1.67 ± 0.08 AP/ 100 pA, n=11, p<0.001, two-tailed unpaired t-test, t=6.51), demonstrating that the effects of chronic stress on excitability were not caused by a reduction of GABAergic inhibition.