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Phototransduction. Eric Niederhoffer SIU-SOM. Retina and photoreceptor Rhodopsin Excitation - recovery/adaptation Cyclic nucleotide gated channels. Retina and Photoreceptor. http://www.fz-juelich.de/inb/inb-1/Photoreception/.
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Phototransduction Eric Niederhoffer SIU-SOM • Retina and photoreceptor • Rhodopsin • Excitation - recovery/adaptation • Cyclic nucleotide gated channels
Retina and Photoreceptor http://www.fz-juelich.de/inb/inb-1/Photoreception/ http://www.mardre.com/homepage/mic/tem/samples/bio/ros/rosdiag.html
bathorhodopsin lumirhodopsin Rhodopsin* metarhodopsin I h Opsin + trans-retinal retinol RPE Rhodopsin cis-retinal Rhodopsin Metarhodopsin II (t1/2 ~ 60 s)
hv GMP GTP GDP I Ta GTP Tbg Ta Ta I GDP GTP Rh PDE PDE RPE65 Rh tR cR tR RK Rh GC Rc Low [Ca2+] tR PPP cGMP Low [Ca2+] GCAP-1 cGMP cGMP Arr GTP Excitation - Recovery/Adaptation CaM CNGC cGMP Na+ Ca2+ c-tR cGMP Excitation Recovery/Adaptation K+ Ca2+ Na+
Review Questions • Which ions and ion channels are used for phototransduction? • Which signal transduction pathway is used for phototransduction (enzymes, second messenger, receptor)? • How does phototransduction compare with gustation and olfaction?