title: TRPM3 expression in mouse retina.
abstract: Transient receptor potential (TRP) channels constitute a large family of cation permeable ion channels that serve crucial functions in sensory systems by transducing environmental changes into cellular voltage and calcium signals. Within the retina, two closely related members of the melastatin TRP family, TRPM1 and TRPM3, are highly expressed. TRPM1 has been shown to be required for the depolarizing response to light of ON-bipolar cells, but the role of TRPM3 in the retina is unknown. Immunohistochemical staining of mouse retina with an antibody directed against the C-terminus of TRPM3 labeled the inner plexiform layer (IPL) and a subset of cells in the ganglion cell layer. Within the IPL, TRPM3 immunofluorescence was markedly stronger in the OFF sublamina than in the ON sublamina. Electroretinogram recordings showed that the scotopic and photopic a- and b-waves of TRPM3(-/-) mice are normal indicating that TRPM3 does not play a major role in visual processing in the outer retina. TRPM3 activity was measured by calcium imaging and patch-clamp recording of immunopurified retinal ganglion cells. Application of the TRPM3 agonist, pregnenolone sulfate (PS), stimulated increases in intracellular calcium in ~40% of cells from wild type and TRPM1(‑/‑) mice, and the PS-stimulated increases in calcium were blocked by co-application of mefenamic acid, a TRPM3 antagonist. No PS-stimulated changes in fluorescence were observed in ganglion cells from TRPM3(-/-) mice. Similarly, PS-stimulated currents that could be blocked by mefenamic acid were recorded from wild type retinal ganglion cells but were absent in ganglion cells from TRPM3-/- mice.
authors: Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States of America; WWAMI Medical Education Program, Washington State University, Pullman, Washington, United States of America.
authors: R Lane
authors: RL
authors: Brown
authors: Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Wei-Hong
authors: WH
authors: Xiong
authors: Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States of America.
authors: James H
authors: JH
authors: Peters
authors: Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Merve
authors: M
authors: Tekmen-Clark
authors: Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Iwona
authors: I
authors: Strycharska-Orczyk
authors: Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States of America; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Brian T
authors: BT
authors: Reed
authors: Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Catherine W
authors: CW
authors: Morgans
authors: Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon, United States of America.
authors: Robert M
authors: RM
authors: Duvoisin
mesh_terms: D000818:Animals; D016466:CHO Cells; D020013:Calcium Signaling / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D004596:Electroretinography; D015870:Gene Expression; D051379:Mice; D008822:Mice, Transgenic; D011284:Pregnenolone / Q000494:pharmacology; D020033:Protein Isoforms; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics* / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D050053:TRPM Cation Channels; C533868:TRPM3 protein, mouse; C018370:pregnenolone sulfate; D011284:Pregnenolone