This volume, and its companion Volume 316, include newly developed methods to study vertebrate phototransduction and the visual cycle. Major topics covered include expression, isolation, and characterization of opsins; proteins that interact with rhodopsin; transducin and regulators of G-protein signaling; photoreceptor protein phosphatases, phosphodiesterase, and guanylylcyclase; cyclis nucleolide gated channels; Na+/Ca2+-K+ exchanges and ABCR transporter.The critically acclaimed laboratory standard for more than forty years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. Now with more than 300 volumes (all of them still in print), the series contains much material still relevant today—truly an essential publication for researchers in all fields of life sciences.