Figure 7.

Effects of chronic glaucoma and 8-OH-DPAT on the frequency/amplitude of mIPSCs and the synaptic connections between RGCs and amacrine cells. A, Representative traces of whole-cell voltage-clamp recordings of GABAergic mIPSCs in the presence of TTX (1 μm) in control, glaucoma, and glaucoma + 8-OH-DPAT retinas. Vertical bar, 10 pA; horizontal bar, 0.5 s. The baseline mIPSC frequency is significantly reduced in the glaucomatous retina relative to that in the control and 8-OH-DPAT can reverse the decrease in mIPSCs in the pathological state. B, C, Histograms showing the mean frequency and amplitude of mIPSCs in control, glaucoma, and glaucoma + 8-OH-DPAT retinas. The mIPSC frequency differed significantly between the control and glaucomatous retinas and glaucoma-induced changes were promoted by 8-OH-DPAT. The mIPSC amplitude was significantly changed before and after preincubation of the glaucomatous slice with 8-OH-DPAT (*p < 0.05 and **p < 0.01, one-way ANOVA). D, Micrograph in D1 was taken with an infrared interferometric phase microscope and the retinal layers can be seen. D2–D4, Using a fluorescence microscope, the cell morphology becomes apparent: dendritic arborizations are found in the IPL. The amacrine cell body is pear shaped (arrow) and mainly distributed in the INL/IPL border. Morphologically, the synaptic connections between RGCs and amacrine cells were not dissociated due to glaucoma (D2, D3) and pretreatment with 8-OH-DPAT did not increase the number of synapses (D4). Scale bar, 10 μm.