The Vertebrate Retina
The retina, like other parts of the CNS, derives embryologically from the neural tube. Retinal neurons and glia therefore have many properties in common with other CNS tissue, but they also exhibit specialized response properties and proteins that have evolved to serve the retina’s function in transducing light energy into nerve signals and analyzing the visual image. For example, to encode small changes in light intensity, many retinal neurons respond to light with graded changes in membrane potential and do not exhibit sodium-dependent action potentials. In addition to possessing the specialized proteins needed for phototransduction (e.g., rhodopsin and transducin), the retina contains a number of proteins specialized for the transmission and processing of visual information such as the metabotropic glutamate receptor, mGluR6, in ON type bipolar cells; the GABAc receptor (Lukasiewicz et al., 2004); and the alpha 1F calcium channel subtype in rod photoreceptors. This chapter summarizes some of the special features of retina that help it to transduce and process light.
KeywordsAmacrine cell Bipolar cell Cone Fovea Horizontal cell Müller cells Photoreceptor Retina Retinal ganglion cell Rod
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