title: Stimulus-evoked outer segment changes occur before the hyperpolarization of retinal photoreceptors.
abstract: Transient retinal phototropism (TRP) has been predominantly observed in rod photoreceptors activated by oblique visible light stimulation. Dynamic confocal microscopy and optical coherence tomography (OCT) have revealed rod outer segment (ROS) movement as the physical source of TRP. However, the physiological source of ROS movement is still not well understood. In this study, concurrent near-infrared imaging of TRP and electroretinogram (ERG) measurement of retinal electrophysiology revealed that ROS movement occurs before the onset of the ERG a-wave, which is known to reflect the hyperpolarization of retinal photoreceptors. Moreover, substitution of normal superfusing medium with low-sodium medium reversibly blocked the photoreceptor ERG a-wave, but largely preserved the stimulus-evoked ROS movements. Our experimental results and theoretical analysis indicate that early, disc-based stages of the phototransduction cascade, which occur before the hyperpolarization of retinal photoreceptors, contribute to the TRP associated ROS movement.
authors.affiliation: Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Benquan
authors.initials: B
authors.lastname: Wang
authors.affiliation: Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Pepperberg
authors.affiliation: Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA; Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA.
authors.forename: Xincheng
authors.initials: X
authors.lastname: Yao
keywords: (170.1530) Cell analysis; (170.4470) Ophthalmology; (330.4270) Vision system neurophysiology; (330.4595) Optical effects on vision; (330.5310) Vision - photoreceptors; (330.5370) Physiological optics; (330.5380) Physiology; (330.7331) Visual optics, receptor optics