Figure 4.

Kir4.1 dsRNA injection into the trigeminal ganglion. A1, Injection of Kir4.1 dsRNA into the trigeminal ganglion inhibits the expression of Kir4.1 as shown by reduced SGC immunolabeling (green). A2, A3, Pseudocolor representation of the squares depicted in A1 shows that Kir4.1 inhibition is greatest close (A2) to the injection site indicated by the red fluorescent dye DiI (A1, arrow) when compared with a distant area (A3). B, C, Serial sections from a Kir4.1 dsRNA injection site showing that, after the disappearance of Kir4.1 immunoreactivity (B, green), SGCs are still present as indicated by GLAST labeling (C, green). The asterisk shows the same blood vessel on each section (B, C). D, Kir5.1 immunolabeling (green) is still present in SGCs after Kir4.1 dsRNA injection (arrow shows DiI injection site). E, Immunostaining for SK3 (green) from the region of the trigeminal ganglion injected with Kir4.1 dsRNA indicated by the presence of DiI (red, arrow). There is no reduction of the SGC-specific SK3. F, Kir2.3 immunostaining (green) from the region of the trigeminal ganglion injected with Kir4.1 dsRNA indicated by the presence of DiI (red). There is no reduction of the Kir2.3 immunostaining. G, Section from a Kir4.1 dsRNA injection site (arrows indicate DiI, showing we are in the injection site) on day 14 showing the return of Kir4.1 expression (green). H, Kir4.1 dsRNA injection site showing only a single ATF3-immunopositive neuron (arrow). Inset, Higher magnification of the ATF3-immunolabeled neuron. The asterisk indicates the location of the center of DiI injection. I, Large numbers of ATF3-positive neurons (arrows) are present after CCI of the ION. Scale bars: A, H, 300 μm; B, C, 90 μm; D, I, 30 μm; E, 60 μm; G, I, 180 μm.