Retinal phototransduction

Abstract

Vision is perhaps the most important of all our senses, and gives us an immense amount of information regarding the outside world. The initial format in which this information reaches the retina are photons; particles of energy radiation of a given wavelength emitted or reflected from our surroundings. The brain itself however, perceives information in electrical signals via action potentials and changes in electrochemical gradients. The processes involved in the transduction of photons into electrical potentials will be the focus of this article. This review article summarizes the recent advances in understanding these complex pathways and provides an overview of the main molecules involved in the neurobiology of vision.

Figure 1

The chemical structure and formation of rhodopsin. C - carbon, H - hydrogen, O - oxygen, N - nitrogen, R - rest of the molecule.

Figure 2

Light causes a conformational change in the retinal molecule from the 11 cis-retinal to the trans-retinal. C - carbon, H - hydrogen, O - oxygen.

Figure 3

A schematic summary of the light conduction pathway. GDP - guanosine diphosphate, GTP - guanosine triphosphate, GMP - guanosine monophosphate, Na⁺ - sodium ions, Ca²⁺ - calcium ions, K⁺ - potassium ions.