Fig. 1: Local electrical stimulation evokes intracellular ATP response in cortical neurons in vivo.
From: Intracellular ATP levels in mouse cortical excitatory neurons varies with sleep–wake states
a Schematic illustration of the fiber photometric system. For the recording of Thy1-ATeam mice, the fluorescence emission is separated by a dichroic mirror. Yellow and cyan fluorescence signals are corrected by band-pass filters and enhanced by photomultiplier tubes (PMTs). For the recording of CaMKII-GCaMP, one light pathway for fluorescence emission and PMT was used. Dashed white line, optical fiber. LED, light-emitting diode. Scale bar = 200 μm. b Schematic illustration of optical fiber with a stimulation electrode implanted in the cortex for Thy1-ATeam or CaMKII-GCaMP monitoring. To monitor cerebral blood flow (CBF), the laser Doppler flowmetry (LDF) probe is positioned over the skull where the electrode is implanted. Scale bar = 1 mm. c ATP signals during local electrical stimulation at different frequencies. Signals are normalized between one (mean of 5 s before stimulation) and zero (trough value after 50 Hz stimulation) in each animal and presented as mean (n = 6 mice). d ATP signals represented as area under the curve (AUC). *p < 0.05 and **p < 0.01; one-way ANOVA, Bonferroni test (AUC value for 5 s before stimulation vs. that for 60 s after stimulation; n = 6 mice), mean ± SEM. e CaMKII-GCaMP signals during local stimulation. Signals are normalized between zero (mean of 5 s before stimulation) and one (peak value after 50 Hz stimulation) in each animal and presented as mean value (n = 6 mice). f The AUC of CaMKII-GCaMP signals following stimulation. g CBF during local stimulation. Normalization as in (e) (n = 7 mice). h CBF response as AUC. i Maximum response time of Thy1-ATeam, CaMKII-GCaMP, and CBF following stimulation. **p < 0.01 vs. CaMKII-GCaMP; ††p < 0.01 vs. CBF; ##p < 0.01 vs. time of the end of stimulation; Student’s t-test with Bonferroni correction, mean ± SEM. j Recovery half-time of Thy1-ATeam, CaMKII-GCaMP, and CBF following stimulation. *p < 0.05 and **p < 0.01 vs. CaMKII-GCaMP; †p < 0.05 and ††p < 0.01 vs. CBF; Student’s t-test with Bonferroni correction.
