Figure 2. Coimmunostaining of P1 foveal glial cells with the Müller cell marker, GS, and GFAP. Coimmunostaining of foveal cryosections from P1 with glutamine synthetase (GS), which is a specific marker of Müller cells in humans, and with glial fibrillar acidic protein (GFAP) which stains astrocytes and activated retinal Müller glial cells, shows that GFAP-positive cells constitute the roof of the foveal pit A, B, and inset) and are not stained with GS (C, D, and inset). GFAP stains perivascular astrocytes (B, arrow), and GS stains the Müller cells’ radial extensions at the fovea (E, arrow) and Z-shaped Müller cells in Henle’s fiber layer (F, arrow). Note that the Z-shaped retinal Müller glial cells also express GFAP (F, yellow labeling). GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; HL, Henle’s fiber layer; OLM, outer limiting membrane.