Fig. 5: Chronic stress and loss of the GluK1-GABA_B-dependent tonic inhibition regulates LA output to CeL.

A Voltage clamp recordings of sEPSCs from PKCδ+ and PKCδ- neurons in CeL, in acute slices from control and CRS-exposed PKCδ-TdTom mice. Pooled data on the sEPSC frequency in the two cell types (PKCδ+: control, n = 19 (7 mice), CRS, n = 16 (5 mice), t-test, t = 3.302, df = 33, **p = 0.0023; PKCδ-: control, n = 9 (4 mice), CRS, n = 9 (5 mice), t-test, t = 1.848, df = 6, p = 0.1140). B The experimental approach for chemogenetic inhibition of the BLA PNs in PKCδ-Cre mice. AAV viral vectors encoding for inhibitory DREADD receptor hM4Di under the CaMKII promoter were injected into the BLA to target PNs. PKCδ+ neurons in the CeL were visualized by injection of AAV viral vectors encoding Cre-dependent EGFP. C The effect of CNO (10 μM) on resting membrane potential (RMP, recorded under whole cell current clamp) and spontaneous AP firing (cell-attached recording) in hM4Di expressing BLA PNs. CNO application resulted in 6.4 ± 1.8 mV hyperpolarizing shift in the membrane potential and 28 ± 10% reduction in the frequency of spontaneous AP firing (RMP: n = 6 (3 mice), paired t-test, t = 3.468, df = 5, *p = 0.0179; AP : n = 13 (3 mice), one sample t-test, t = 2.655, df = 12, *p = 0.021). D Examples of sEPSC recordings from PKCδ+ neurons in slices from control and CRS-exposed mice, expressing the inhibitory DREADD receptor hM4Di in the BLA PNs, at control conditions and in the presence of CNO (10 µM). Pooled data on the effect of CNO on sEPSC frequency (control: baseline, n = 11, CNO, n = 10 (4 mice), paired t-test, t = 2.746, df = 19, *p = 0.0128; CRS: baseline, n = 10, CNO, n = 8 (4 mice), paired t-test, t = 4.493, df = 16, ***p = 0.0004). Comparisons between control vs. CRS: unpaired t-test, t = 3.836, df = 19, **p = 0.0011; control + CNO vs. CRS+CNO: unpaired t-test, t = 1.204, df = 16, p = 0.2463. E Example traces and pooled data on sEPSC recordings from PKCδ+ neurons before and after application of ACET (200 nM) in control and CRS-exposed animals (control: n = 12 (5 mice), paired t-test, t = 4.452, df = 11, ***p = 0.001; CRS: n = 7 (5 mice), paired t-test, t = 0.7174, df = 6, p = 0.50). F Examples of sEPSC recordings from PKCδ+ neurons before and after application of ACET (200 nM) in mice expressing hM4Di in the BLA, in absence or continuous presence of CNO. Pooled data on the effect of ACET on sEPSC frequency (hM4Di: n = 6 (4 mice), paired t-test, t = 4.881, df = 5, **p = 0.0045; hM4Di + CNO: n = 6 (4 mice), paired t-test, t = 1.447, df = 5, p = 0.2074). All the data presented as mean ± SEM.