Fig. 2.

Developmental expression of Kir4.1 in astrocytes. Double immunofluorescence labelling for Kir4.1 (green) and GFAP (red), at P10 (A), P15 (B) and P20 (C,D). (A) In the P10 nerve, there was little co-labelling for GFAP and Kir4.1 (curved arrow), and GFAP⁺/Kir4.1⁺ astrocytes were rarely observed (arrow); co-expression appears yellow–orange. The majority of Kir4.1⁺ cells did not express GFAP (arrowhead). (B) In the P15 nerve, there was extensive co-labelling for GFAP and Kir4.1 (arrows), together with numerous GFAP⁻/Kir4.1⁺ profiles (arrowheads). (C) A GFAP⁺/Kir4.1⁺ astrocyte (arrow) within a row of GFAP⁻/Kir4.1⁺ presumptive oligodendrocytes (arrowhead) in the P20 nerve. (D) Stellate astrocytes at the optic chiasm, indicating most if not all astrocytes express Kir4.1. Scale bars: 30 µm (B,C); 50 µm (A,D).