title: Glutamatergic neurotransmission from melanopsin retinal ganglion cells is required for neonatal photoaversion but not adult pupillary light reflex.
abstract: Melanopsin-expressing retinal ganglion cells (mRGCs) in the eye play an important role in many light-activated non-image-forming functions including neonatal photoaversion and the adult pupillary light reflex (PLR). MRGCs rely on glutamate and possibly PACAP (pituitary adenylate cyclase-activating polypeptide) to relay visual signals to the brain. However, the role of these neurotransmitters for individual non-image-forming responses remains poorly understood. To clarify the role of glutamatergic signaling from mRGCs in neonatal aversion to light and in adult PLR, we conditionally deleted vesicular glutamate transporter (VGLUT2) selectively from mRGCs in mice. We found that deletion of VGLUT2 in mRGCs abolished negative phototaxis and light-induced distress vocalizations in neonatal mice, underscoring a necessary role for glutamatergic signaling. In adult mice, loss of VGLUT2 in mRGCs resulted in a slow and an incomplete PLR. We conclude that glutamatergic neurotransmission from mRGCs is required for neonatal photoaversion but is complemented by another non-glutamatergic signaling mechanism for the pupillary light reflex in adult mice. We speculate that this complementary signaling might be due to PACAP neurotransmission from mRGCs.
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Anton
authors.initials: A
authors.lastname: Delwig
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: Sriparna
authors.initials: S
authors.lastname: Majumdar
authors.affiliation: Department of Anatomy, University of California San Francisco, San Francisco, California United States of America.
authors.forename: Kelly
authors.initials: K
authors.lastname: Ahern
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America ; Department of Anatomy, University of California San Francisco, San Francisco, California United States of America.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: LaVail
authors.affiliation: Department of Physiology, University of California San Francisco, San Francisco, California, United States of America ; Department of Neurology, University of California, San Francisco San Francisco, California, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Edwards
authors.affiliation: Department of Neurology, University of California, San Francisco San Francisco, California, United States of America ; Department of Neurosciences, University of California San Diego, San Diego, California, United States of America.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hnasko
authors.affiliation: Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America ; Department of Physiology, University of California San Francisco, San Francisco, California, United States of America.
authors.forename: David R
authors.initials: DR
authors.lastname: Copenhagen
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D005260:Female; D007124:Immunoenzyme Techniques; D019426:Integrases / Q000378:metabolism; D008027:Light; D055537:Light Signal Transduction; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018377:Neurotransmitter Agents / Q000378:metabolism; D010775:Photic Stimulation; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D012025:Reflex, Pupillary / Q000502:physiology* / Q000528:radiation effects; D012165:Retinal Ganglion Cells / Q000378:metabolism* / Q000528:radiation effects; D017299:Rod Opsins / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D050599:Vesicular Glutamate Transport Protein 2 / Q000502:physiology*; D014786:Vision Disorders; D014785:Vision, Ocular / Q000502:physiology / Q000528:radiation effects; D000099210:Melanopsin
chemical_list: D019426:Integrases; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D017299:Rod Opsins; D050599:Vesicular Glutamate Transport Protein 2; D000099210:Melanopsin; C493477:Slc17a6 protein, mouse; C045073:Cre recombinase