Figure 2: Representative schematic illustration showing PACAP and PAC1 distribution in rodent retina. Immunohistochemical studies have shown that PACAP immunoreactivity (IR) is detectable in nerve fibers (neurites) originating from retinal ganglionic cells as well as in neuronal cell bodies of amacrine and horizontal cells in the inner nuclear layer. No evidence of PACAP-IR has been provided in photoreceptors in the outer nuclear layer (ONL) or in the retinal pigmented epithelium (RPE) [22, 28, 29].