Rapid Light-induced Potentials Common to Plant and Animal Tissues

Abstract

IRRADIATION of retinal tissue by brief intense flashes of light produces rapid changes in electrical potential. These changes, which occupy only 2–3 msec, are characterized by an initial cornea-positive wave followed by a negative one, and have been referred to collectively as the “early receptor potential” or e.r.p.1. Spectral sensitivity measurements clearly demonstrate that the e.r.p. results from the absorption of light by retinal rhodopsin2, but recent studies (in this and other laboratories) have revealed that an apparently similar potential can be obtained from flash irradiated tissues containing sufficiently high concentrations of melanin (for example, ocular pigment epithelium3,4, iris5 and frog skin5). This communication reports that yet another pigmented tissue, the green leaf, will also produce an “e.r.p. type” potential when irradiated under identical conditions. Important similarities, not only of waveform and time course but also in response to temperature change, suggest that there is a common fundamental mechanism.