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Richard Kramer"How photoreceptor synapses in the retina transmit the light response"

Abstract :

Rod and cone photoreceptors transmit information to other neurons through specialized structures called ribbon synapses.
Unlike most synapses, ribbon synapses continuously release neurotransmitter, with light causing a decrease in the rate of release.
We are using lipophilic fluorescence dyes, along with 2-photon, confocal, and electron microscopy, to track the life cycle of synaptic vesicles in photoreceptor terminals. This process starts with endocytosis, includes interactions with the synaptic ribbon, and ends with exocytosis.
We are also examining how light and synaptic feedback regulate exocytosis from rods and cones. The use of activity-dependent dyes to stain synaptic vesicles allows investiagation of individual synapses and the behavior of 2-dimensional arrays of synapses while the retina is resonding to visual images.

Selected publications

Role of the synaptic ribbon in transmitting the cone light response.Jackman SL, Choi SY, Thoreson WB, Rabl K, Bartoletti TM, Kramer RH. Nat Neurosci. 2009 Mar;12(3):303-10. Epub 2009 Feb 15.

Light-activated ion channels for remote control of neural activity. Chambers JJ, Kramer RH. Methods Cell Biol. 2008;90:217-32.Light-activated ion channels for remote control of neural activity. Chambers JJ, Kramer RH. Methods Cell Biol. 2008;90:217-32.

Light regulation of Ca2+ in the cone photoreceptor synaptic terminal. Choi SY, Jackman S, ThoresoWB, Kramer RH. Vis Neurosci. 2008 Sep-Dec;25(5-6):693-700.

Photochemical control of endogenous ion channels and cellular excitability. Fortin DL, Banghart MR, Dunn TW, Borges K, Wagenaar DA, Gaudry Q, Karakossian MH, Otis TS, Kristan WB, Trauner D, Kramer RH. Nat Methods. 2008 Apr;5(4):331-8.

Remote control of neuronal activity with a light-gated glutamate receptor. Szobota S, Gorostiza P, Del Bene F, Wyart C, Fortin DL, Kolstad KD, Tulyathan O, Volgraf M, Numano R,Aaron HL, Scott EK, Kramer RH, Flannery J, Baier H, Trauner D, Isacoff EY. Neuron. 2007 May 24;54(4):535-45.

Valentin Nagerl