Citation | Denis Baylor is internationally renowned for elucidating the mechanisms by which light energy is converted into a neural signal within the rod and cone photoreceptors of the eye. In the late 1960s he pioneered the technique of intracellular electrical recording from photoreceptors in the vertebrate retina, and in the early 1970s undertook an extremely productive collaboration with Alan Hodgkin in Cambridge, which led to major advances in the quantitative understanding of phototransduction. Since 1974, Baylor has been at the Department of Neurobiology at Stanford University, where he has repeatedly made major advances. He and his colleagues developed the `suction pipette' technique for recording the electrical current from individual photoreceptor cells, and applied the method to show that rod photoreceptors could respond to individual photons of light; he measured the rate of thermal isomerization in the rods, and showed that these events limit our vision in extremely dim illumination. The suction pipette method proved so successful that it became the standard recording technique throughout the world. Baylor recorded successfully from the tiny rods and cones of primates, and in doing so he established the electrophysiological basis for many aspects of human vision, including the speed of the response, its saturation with intensity, its adaptation by background light, and the basis for trichromacy. In recent years, he has pioneered the investigation of the molecular basis of transduction in photoreceptors, by combining the techniques of molecular biology with those of electrophysiology. He has established the roles of rhodopsin phosphorylation, and the actions of two regulatory molecules (arrestin and recoverin) in terminating the rod's electrical response to illumination. Through Baylor's work, we now understand the basis of the photoreceptor's electrical response to light at a molecular level. What makes his work so compelling is the combination of sophisticated biophysical and molecular techniques with rigorous quantitative analysis, in a manner that always keeps the underlying biological problem in perspective. |