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. Author manuscript; available in PMC: 2019 Feb 1.
Published in final edited form as: Neurobiol Dis. 2017 Nov 13;110:47–58. doi: 10.1016/j.nbd.2017.11.003

Figure 2. Photostimulation of 5-HT neurons in the DR reduces S-IRA evoked by acoustic stimulation.

Figure 2

A, compared with the incidence of S-IRA evoked by acoustic stimulation 24 hr prior to photostimulation, S-IRA was significantly reduced by photostimulation at 9 mW for 15 min in transgenic DBA/1 mice (n = 15). However, photostimulation at 9 mW for 1 (n = 8), 5 (n = 6) or 10 min (n = 6) exerted no effect on S-IRA evoked by acoustic stimulation. B, increasing energy level to 15 mW significantly suppressed S-IRA evoked by acoustic stimulation for a shorter photostimulation duration of 5 min in transgenic DBA/1 mice (n = 6), although a further decrease in stimulation duration to 3 min produced no significant effect on S-IRA (n = 4) as compared to that observed 24 hr prior to photostimulation. C, D, for each stimulation duration, bar graphs or box plots show that photostimulation at either 9 mW or 15 mW did not alter the latency to AGSz in transgenic DBA/1 mice as compared with that tested 24 hr prior to photostimulation. E, F, for each stimulation duration, bar graphs or box plots show that photostimulation at either 9 mW or 15 mW did not affect the duration of wild running and clonic seizures in transgenic DBA/1 mice as compared with that tested 24 hr prior to photostimulation. G, H, for the transgenic DBA/1 mice in which S-IRA evoked by acoustic stimulation was suppressed by photostimulation, susceptibility of these mice to S-IRA evoked by acoustic stimulation returned 24–72 hr after photostimulation at 9 mW for 15 min and 24–48 hr after photostimulation at 15 mW for 5 min, respectively. Blank bars, the incidence of S-IRA, the latency to AGSz and the duration of wild running and clonic seizures evoked by acoustic stimulation 24 hr prior to photostimulation; red bars, the incidence of S-IRA, the latency to AGSz and the duration of wild running and clonic seizures following photostimulation at 9 mW; orange bars, the incidence of S-IRA, the latency to AGSz and the duration of wild running and clonic seizures following photostimulation at 15 mW; green bars, the return of the susceptibility to S-IRA after photostimulation. N-PS, no photostimulation. W/C, wild running and clonic seizures. Photostimulation parameters: blue light, 473 nm; pulse duration, 20 ms; frequency, 20 Hz.

** p < 0.01; *** p < 0.001: Significantly different from the incidence of S-IRA evoked by acoustic stimulation 24 hr prior to photostimulation.