Fig. 3: Photoacoustic responses under pharmacological blocking.
a Percentage of retinal ganglion cells (RGCs) modulated by photoacoustic (PA) stimulation per stimulation site before and after group III mGluR agonist L-AP4 application (2 retinae, n = 9 stimulation sites). b L-AP4 decreased RGC spontaneous firing rate and firing rate during PA-elicited responses in Long Evans (LE) retinae. The population firing rate of RGCs (n = 41 cells, 2 retinae) is compared between baseline (Basal) and stimulation (Stim.), before blocker application (No blocker), following blocker application (L-AP4) and after washout (Washout) with Ringer medium. Significance of differences between frbasal and frstim per condition, no blocker: P < 0.001; L-AP4: P < 0.001; L-AP4 + ACET: P = 0.024; washout: P < 0.001. c L-AP4 increases response latency in LE retinae. Response latency per condition (n = 41 cells, 2 retinae), no blocker: 49 ± 5 ms; L-AP4: 65 ± 4 ms; washout: 42 ± 3 ms. Due to absence of responses during application of L-AP4 + ACET blockers, no latencies are reported for this group. Dashed black line: 45-ms cutoff for slow- and fast-latency responses. d Percentage of cells modulated by photoacoustic stimulation per stimulation site before and after (rs)-CPP and CNQX application in P23H retinae (2 retinae, n = 5 stimulation sites). e Glutamate blockers (rs)-CPP and CNQX abolished RGC responses to PA stimulation in P23H retinae (n = 25 cells, 2 retinae). Significance per condition, frbasal vs frstim: no blocker: P < 0.001; (rs)-CPP + CNQX: P = 0.141; washout: P = 0.016. Significance stimulation firing rate frstim after blocker application and frstim before application (P < 0.001, two-sided Wilcoxon signed-rank), and frstim after washout (P < 0.001, two-sided Wilcoxon signed-rank). For each panel, groups are tested for significant differences using Friedman chi square, with post-hoc two-sided Wilcoxon signed-rank. p-values are holm-corrected (***: P < 0.001, **: P < 0.05). Box plots (a–e) central line: median, lower and upper bounds: first (Q1) and third quartiles (Q3), whiskers extend to the most extreme data points within 1.5 times the interquartile range from Q1 and Q3. Dashed line: mean.
