Optogenetics

Abstract

The use of light or laser therapy as a tool to manipulate cellular processes in various biological fields has rapidly developed over the past decade. Laser light can be used to study the mechanisms underlying the changes in cellular processes, and the addition of photosensitive proteins has facilitated the difficult experimentation necessary to elucidate and control the processes which direct intracellular mechanisms, map neuronal pathways, and alter variables that previously were difficult to control, and this modality is called optogenetics. Optogenetics can be defined as the use of light (photons) to control the activities or behaviors of a cell that has been modified to express optically active proteins. The effect of the laser therapy or optogenetics depends on the use of a specific wavelength which affects the light sensitive targets. As optogenetics depends on light, the choice of light source is a very important factor in optogenetic experiments. Some important things for the researcher to consider when discriminating between light sources are the range of emission wavelengths, the excitation wavelength for opsin activation, power, scattering, and other factors. Rhodopsin and its associated variants are the photosensitive proteins most commonly employed in optogenetics. Rhodopsin and other opsins providing the structural basis for optogenetics have been discovered and isolated from many different organisms. Optogenetics has the advantage of giving the investigator a precise spatial and temporal control over experimental variables. This book chapter focuses on use of optogenetics in biological fields and the biology and role of various channelrhodopsins in elucidating various molecular mechanisms and biological processes.