Fig. 5
From: Supramammillary glutamate neurons are a key node of the arousal system
SuM GABA/glutamate co-releasing neurons. a In situ hybridization for vglut2 (magenta) in a vgat-IRES-Cre/L10 reporter mouse (green, see Methods section) reveals vglut2/vgat co-expression (white). b These neurons constitute a subpopulation of the larger neurons of the grandicellular SuM (partially opaque). c Cartoon showing AAVx-FLEX-ChR2-mCherry recombining in the presence of Cre in either vglut2-Cre or vgat-Cre mice. d Cartoon of optogenetically evoked stimulation of SuM terminals on dentate gyrus grandule cells, superimposed on a histological image showing dense anterograde labeling (AAV-FLEX-GFP in vgat-Cre mouse) of SuM terminals in the dentate gyrus supragranular layer and CA2 (dark brown) with a light Nissl counterstain (faint blue−purple; scale bar 500 µm). e Representative brain-slice voltage-clamp recording a dentate gyrus granule cell during photostimulation of SuMvgat terminals expressing ChR2-YFP in vgat-IRES-Cre mice (Vh = −70 mV; KCl-based pipette solution; three 5 ms light pulses: blue bars). Photo-evoked postsynaptic currents (average of 30 trials) recorded in control ACSF (Con), in bicuculline-methiodide (Bic, 10 µM), in DNQX (20 nM) and DNQX + Bic. f Half-width of GABA-A-mediated and AMPA-mediated photo-evoked postsynaptic currents (30 trials, 3 neurons; mean ± SEM in red; p < 0.001unpaired t-test). g Photo-evoked (SuMVgat → DG) GABA-A-mediated (left) and AMPA-mediated (right) postsynaptic currents recorded at different membrane potential (Cs-based pipette solutions) and h. I−V curves of the GABAA- (black circle) and AMPA- (white circle) postsynaptic currents (mean ± SEM, n = 4). i GABAA- (top trace) and AMPA- (bottom trace) postsynaptic currents evoked by photostimulation of SuMVglut2 → DG input in vglut2-IRES-Cre mice. j Onset delay of GABAA- and AMPA-mediated postsynaptic currents (black circle: vgat-IRES-Cre mice and white circle: vglut2-IRES-Cre mice; mean ± SEM in red; p = 0.002 paired t-test)
