Transient receptor potential cation channel, subfamilies V, member 1 (TRPV1) and M, member 1 (TRPM1) contribute to neural signaling in mouse retina.

ganglion cell;electrophysiology;bipolar cell;LRIT3;vision;nyctalopin

Jennifer Noel

University:University of Louisville

Department:Anatomical Sciences and Neurobiology

关键词: ganglion cell;    electrophysiology;    bipolar cell;    LRIT3;    vision;    nyctalopin;   

Others  :  https://ir.library.louisville.edu/cgi/viewcontent.cgi?article=3689&context=etd

美国|英语

来源: The Universite of Louisville's Institutional Repository

【 摘 要 】

The retina processes light information through parallel pathways in order to extract and encode the visual scene. Light information is transmitted to the brain through approximately 30 ganglion cells (GCs), the retinal output neurons. Trp channels modulate the responses of retinal neurons within specific pathways. The study of the expression and function of the majority of Trp channels in the retina is largely in its infancy. My dissertation first investigated the expression and function of the transient receptor potential vanilloid-1 (TRPV1) receptor/channel in the retina. TRPV1, the first cloned and most highly studied Trp channel in the peripheral nervous system, is a non-selective cation channel with an affinity for Ca2+. The channel can be activated by capsaicin, acid, endovanilloids, noxious heat or pressure (Moreira et al., 2012). Located on the peripheral and central terminals of nociceptive fibers in the PNS and in limited areas of the CNS (Cavanaugh et al, 2011b). TRPV1 plays a role in inflammation, chronic pain, nociceptor sensitization and desensitization, long-term depression and potentiation, and apoptosis. The role of TRPV1 in the retina is not known. Using the electroretinogram (ERG), a mass potential that assesses the function of photoreceptors and bipolar cells, the TRPV1 knockout mouse appears normal. However, TRPV1 is thought to play a role in calcium regulation and glaucoma (Sappington et al., 2009 & Leonelli et al., 2010) so we investigated its role in normal visual transduction in the inner retina. To investigate TRPV1 modulation, I recorded GC spiking responses to light stimuli from mice which either express or lack TRPV1 protein. I found that TRPV1 is critical for: 1. GC responses to dim light. 2. Sustained responses to light 3. Surround suppression of GCs to large spots. Further, I investigate the specific retinal cells that express TRPV1. I used TRPV1cre mice with genetic or viral methods to fluorescently label neurons that express TRPV1. I determined TRPV1 is expressed in four classes of amacrine and three classes of ganglion cells in the inner retina. My results indicate TRPV1 activity in the amacrine cells enhances the sustained spiking responses in GCs. In this way, TRPV1 likely enhances the perception of subtle details in the visual world. TRPV1 also is expressed in subsets of intrinsically photosensitive GCs, which are known to play a role in circadian photoentrainment. TRPV1 therefore has the potential to modulate circadian photoentrainment or other non-image forming visual functions as well. The role of