Fig. 1: Chemogenetic or optogenetic activation of DRNGAD2 neurons decreases wakefulness.
From: A midbrain GABAergic circuit constrains wakefulness in a mouse model of stress
a Schematic of viral injection and EEG/EMG recordings. AAV-EF1α-DIO-hM3Dq-mCherry was injected into the DRN of GAD2-Cre mice for chemogenetic activation. b, c Representative images showing the expression of hM3Dq-mCherry in the DRN (b) and the colocalization of hM3Dq-mCherry with GAD2 mRNA (c). lPAG, lateral periaqueductal gray; vlPAG, ventrolateral periaqueductal gray; Aq, aqueduct. d Quantitative analysis of the efficiency and specificity of hM3Dq-mCherry to label DRNGAD2 neurons. n = 4 mice. e EEG power spectrogram, EMG traces, and hypnograms from a DRNGAD2-hM3Dq mouse during 3 h post saline (left) or CNO (1 mg/kg, right) injection. Freq., frequency; W, wake; NR: NREM; R: REM. f Time spent in each state during the first 3 h after saline or CNO injection. n = 11 mice, two tailed paired t test, wake: t10 = 7.248, P = 2.76 × 10−5; NREM: t10 = 7.128, P = 3.19 × 10−5; REM: t10 = 1.703, P = 0.119. g Schematic of viral injection and EEG/EMG recordings. AAV-EF1α-DIO-ChR2-mCherry was injected into the DRN of GAD2-Cre mice for optogenetic activation. h, i Example images showing the expression of ChR2-mCherry in the DRN (h) and the colocalization of ChR2-mCherry with GAD2 mRNA (i). j Quantitative analysis of the efficiency and specificity of ChR2-mCherry to label DRNGAD2 neurons. n = 3 mice. k EEG power spectrogram, EMG trace, and hypnogram showing optogenetic activation of DRNGAD2 neurons from a DRNGAD2-ChR2 mouse during the light phase. Laser stimulation is indicated by blue stripe. l Top, brain states of recorded trials from DRNGAD2-ChR2 mice. Bottom, percentage of wake, NREM, or REM sleep around 20 Hz stimulation of DRNGAD2-ChR2 mice. Shading represents ±SEM. m Quantification of time spent in each state 120 s before and during optogenetic stimulation of DRNGAD2 neurons. n = 6 mice, two tailed paired t test, wake: t5 = 4.775, P = 0.00499; NREM: t5 = 5.243, P = 0.00335; REM: t5 = 1.425, P = 0.214. **P < 0.01, ***P < 0.001, n.s., not significant. Data (d, f, j, m) are presented as mean ± SEM.
