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. 2017 Nov 8;12(11):e0187732. doi: 10.1371/journal.pone.0187732

Fig 7. Arbitrarily ordered two-color uncaging of glutamate and GABA on dopamine neurons of the substantia nigra.

Fig 7

(a) Example of an experiment showing wavelength-dependent changes in spontaneous firing by activation of AMPA and GABA-A receptors. Left, the frequency of action potentials was decreased by photolysis of DEAC454-GABA with 450 nm light (100 ms, middle) and increased by photolysis of dcPNPP-Glu using 365 nm light (10 ms, middle). Right, simultaneous photolysis resulted in a decrease in the excitation induced by dcPNPP-Glu by activation of GABA-A receptors. Experiments were conducted in cell-attached mode. (b) Summary of change in instantaneous frequency in response to glutamate and GABA uncaging as shown in (a) (n = 6 cells, 3 recordings per cell per condition). Blue line: events when 450 nm light was flashed. Violet line: events when 365 nm light was flashed. Orange line: events when both wavelengths were flashed simultaneously. (c) Summary of change in number of action potentials in response to glutamate and GABA uncaging in 1 s following photolysis as shown in (a) (n = 6 cells, 5–7 recordings per cell per condition). Bars indicate means. Each group represents number of action potentials. Pre: 1 s prior to 450 nm LED flash, 450: 1 s after 450 nm LED, 365: 1 s after 365 nm LED, and Both: 1 s after 450 and 365 nm LEDs flashed simultaneously. A repeated measures two-way ANOVA was used with a post-hoc Tukey test to examine multiple comparisons (all comparisons P < 0.001). (d) Example of an experiment in cell-attached mode showing wavelength-dependent changes in spontaneous firing by activation of AMPA and GABA-B receptors. Left, the frequency of action potentials was decreased by photolysis of DEAC454-GABA using 450 nm light and increased by photolysis of dcPNPP-Glu with 365 nm light. Right, simultaneous photolysis resulted in a decrease in the excitation induced by dcPNPP-Glu by activation of GABA-B receptors. In experiments (a-c), DEAC454-GABA and dcPNPP-Glu were bath-applied at 30 μM and 300 μM, respectively, together with NMDA (CPP, 10 μM), D2 (sulpiride, 2 μM) and GABA-B receptor (CGP-55845a, 500 nM) and mGluR (JNJ-16259685, 1 μM; MPEP, 3 μM) antagonists. In (d), DEAC454-GABA (25 μM) and dcPNPP-Glu (200 μM) were bath-applied together with NMDA (CPP, 10 μM), D2 (sulpiride, 2 μM) and GABA-A receptor (picrotoxin, 10 μM) and mGluR (JNJ-16259685, 1 μM; MPEP, 3 μM) antagonists.