Melanopsin is expressed in the monkey inner retina. Bright-field (A) and dark-field (B) photomicrographs of a section of monkey retina probed with an antisense monkey melanopsin riboprobe.C, An adjacent section probed with a sense control riboprobe. GC, Ganglion cell layer; INL, inner nuclear layer; OD, optic disk; P, photoreceptor layer. Scale bar, 150 μm.