AbstractVision begins in highly specialized light-sensing neurons, the rod and cone photoreceptors. Their task is to absorb photons, transduce the physical stimulus into neuronal signals, transmit the signals to the parallel signal processing pathways of the subsequent retinal network with the highest possible fidelity and continuously adapt to changes in stimulus intensities. If you imagine a pitch-black night with only a few photons hitting the retina and being absorbed by the photoreceptors and a bright sunny day with the photoreceptors being bombarded by billions of photons, you realize that a photoreceptor faces two fundamental challenges: it has to detect the light signal with the greatest sensitivity, e.g. a single photon leads to a change in the membrane potential of a rod photoreceptor and, at the same time, encode light intensities covering a broad dynamic range of several orders of magnitude. To fulfill these demands, photoreceptors have developed separate, structurally and functionally specialized compartments, which are the topic of this article: the outer segment for signal transduction and the terminal with its highly complex ribbon synapse for signal transmission.
Nucleoside Triphosphate (NTP) Binding to Pertussis Toxin and Light Signal Transmission to It Through a Microsomal Fraction of the Stem Section of Etiolated Pea Seedlings.
