Fig. 3: Fasting enhances inhibitory tone within the BNST→LHA^Vglut2 pathway.

A Schematic of viral strategy. AAV-Syn-ChR2-eYFP was injected into BNST and AAV-DIO-mCherry was injected into LHA of Vglut2-Cre mice. Right: example of ChR2 expression in BNST. B mCherry-expressing cells adjacent to eYFP+ axons were targeted for whole-cell patch clamp recordings in acute brain slices. C Example optically evoked IPSC recorded from an LHA^Vglut2 neuron in the presence of TTX and 4AP. IPSCs were abolished by applying gabazine (GBZ) to the bath solution. Two 10-ms pulses spaced 100 ms apart were used to evoke IPSCs. Mean value is represented by thick lines and individual sweeps are overlayed. D IPSCs are evoked by BNST stimulation in the presence of TTX/4AP and eliminated by the application of gabazine to the bath (n = 29 cells from 12 mice; two-tailed paired t test: t(28) = 5.20, p = 1.60 × 10⁻⁵). E Pie chart showing proportion of LHA^Vglut2 neurons exhibiting optically evoked IPSC, EPSC, or both (n = 36 cells from 12 mice). F Paired-pulse ratio (PPR) of optically evoked IPSCs was unchanged by fasting (two-tailed t test: t(26) = 0.06, p = 0.96; n = 14 cells from 6 fed mice and n = 14 cells from 6 fasted mice). G Example traces showing spontaneous IPSCs in fed and fasted mice. Holding current +10 mV. H IPSC rate was increased by fasting (two-tailed t test: t(26) = 2.81, p = 0.009; n = 14 cells from 6 fed mice and n = 14 cells from 6 fasted mice). I IPSC amplitude was unchanged by fasting (two-tailed t test: t(26) = 0.62, p = 0.54; n = 14 cells from 6 fed mice and n = 14 cells from 6 fasted mice). J Spontaneous IPSC rate and optically evoked amplitude were positively correlated (Pearson r = 0.66, p = 0.0001). + symbols represent responses averaged (mean ± SEM) for all cells per mouse in (F, H, I). **p < 0.01, ****p < 0.0001. Source data are provided as a Source Data file.