Fig. 7: RSG is the downstream output of the TMN-SUB histaminergic circuit.
From: Histamine-tuned subicular circuit mediates alert-driven accelerated locomotion in mice
a WT mice were injected with mixed AAV-ESARE-ERT2-Cre-ERT2, AAV-hSyn-DIO-GCaMP6m, and AAV-hSyn-DIO-hM3D(Gq)-mCherry/AAV-hSyn-DIO-hM4D(Gi)-mCherry into SUB. b Expression of hM3D-expressed (top) and hM4D-expressed (bottom) SUB treadmill training-labeled c-fos+ neuron, scale bar = 200 µm. Effects of chemogenetic activation or inhibition of SUB treadmill training-labeled c-fos+ neuron on total distance (c), speed (d) in open field test. n = 7 mice (c: *p = 0.0218, *p = 0.0165; d: *p = 0.0197, *p = 0.0160). e–g Fluorescence value with corresponding speed, and quantification (g) of calcium activity of hM3D-expressed SUB treadmill training-labeled c-fos+ neuron in two groups during acceleration. n = 12 mice (****p < 0.0001). h–j Fluorescence value with corresponding speed, and quantification (j) of calcium activity of hM4D-expressed SUB treadmill training-labeled c-fos+ neuron in two groups during acceleration. n = 12 mice (***p = 0.0002, p = 0.2473). Schematic of injection of mixed AAV-ESARE-ERT2-Cre-ERT2, AAV-EF1a-DIO-EYFP into SUB of WT mice (k), and expression (l) of SUB treadmill training-labeled c-fos+ neuron in SUB with fiber distribution in RSG, AV, MMB. Scale bar = 400 µm. m HDC-CreERT2 mice were injected with AAV-CAG-FLEX-oChIEF-tdTomato into TMN, mixed AAV-ESARE-ERT2-Cre-ERT2, AAV-EF1a-DIO-EYFP into SUB to label TMN-SUB circuit-activated c-fos+ neurons combined with injection of AAV2/2Retro-hSyn-tdTomato into RSG. Viral expression in TMN and RSG, scale bar = 400 um (n), image and quantification (o) of TMN-SUB circuit-activated c-fos+ SUB neurons overlapping with Retro-tdTomato in SUB, n = 3 mice, scale bar = 100 µm. p–s Schematic diagram (p), image (q) of injection of AAV-hSyn-FLEX-ChrimsonR-tdTomato into TMN and AAV2/2Retro-hSyn-GCaMP6s into RSG of the HDC-CreERT2 mice. Scale bar = 100 µm. Fluorescence values, heatmap (r), and quantification (s) of calcium activity of RSG-projecting SUB neurons during TMN-SUB circuit activation. n = 8 mice, **p = 0.0072. Two-tailed Student’s t test for (c, d, g, j, s). Schematics in a, k, m, p were drew by PowerPoint. Bar graphs represent mean ± SEM. Source data are provided as a Source Data file.
