Figure 2
PMEA recordings of isolated WT mice retinae demonstrate a reduction in OFF-RGC responses and a reduction in ON-RGC latency following acute IOP elevation. The pMEA consists of a grid of electrodes, in which the retina rests RGC-side down with the aid of a vacuum pump that applies suction from below (A). Immunohistochemical staining after recording revealed little damage as the RGCs (RBPMS, green) and blood vessels (IB4, red) appeared intact ((B) scale bar 500 µm, magnified inset (C) scale bar 50 µm). (D) Representative peri-stimulus time histograms of RGC cell types in response to light on (white shading) or light off (grey shading). From the left to right of the panel, examples of an ON, OFF, ON–OFF and no-full-field-response cell are presented. (E–G) OFF-RGCs show a reduction in average spontaneous spike rate (E) and maximum spike rate (F) following elevated IOP (red bars) relative to sham eyes (clear bars). ON-RGCs show a reduction in latency to peak following elevated IOP (G). Numbers indicate the number of cells recorded from n = 6–10 animals. The spontaneous activity and light-elicited responses were averaged per retina and are presented for sham (black) and elevated IOP (red) for ON (H), OFF (I) and ON–OFF (J) RGCs. Insets show the spontaneous rate of cells from sham and elevated IOP eyes. *p < 0.05, **p < 0.01; Mann–Whitney test (sham vs IOP).
