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dc.contributor.authorMazzolini, Monica
dc.contributor.authorFacchetti, Giuseppe
dc.contributor.authorAndolfi, Laura
dc.contributor.authorZaccaria, Remo Proietti
dc.contributor.authorTuccio, Salvatore
dc.contributor.authorTreud, Johannes
dc.contributor.authorAltafini, Claudio
dc.contributor.authorDi Fabrizio, Enzo M.
dc.contributor.authorLazzarino, Marco
dc.contributor.authorRapp, Gert
dc.contributor.authorTorre, Vincent
dc.date.accessioned2015-08-03T12:34:57Z
dc.date.available2015-08-03T12:34:57Z
dc.date.issued2015-05-04
dc.identifier.citationMazzolini, M., Facchetti, G., Andolfi, L., Proietti Zaccaria, R., Tuccio, S., Treu, J., … Torre, V. (2015). The phototransduction machinery in the rod outer segment has a strong efficacy gradient. Proceedings of the National Academy of Sciences, 112(20), E2715–E2724. doi:10.1073/pnas.1423162112
dc.identifier.issn00278424
dc.identifier.pmid25941368
dc.identifier.doi10.1073/pnas.1423162112
dc.identifier.urihttp://hdl.handle.net/10754/564170
dc.description.abstractRod photoreceptors consist of an outer segment (OS) and an inner segment. Inside the OS a biochemical machinery transforms the rhodopsin photoisomerization into electrical signal. This machinery has been treated as and is thought to be homogenous with marginal inhomogeneities. To verify this assumption, we developed a methodology based on special tapered optical fibers (TOFs) to deliver highly localized light stimulations. By using these TOFs, specific regions of the rod OS could be stimulated with spots of light highly confined in space. As the TOF is moved from the OS base toward its tip, the amplitude of saturating and single photon responses decreases, demonstrating that the efficacy of the transduction machinery is not uniform and is 5-10 times higher at the base than at the tip. This gradient of efficacy of the transduction machinery is attributed to a progressive depletion of the phosphodiesterase along the rod OS. Moreover we demonstrate that, using restricted spots of light, the duration of the photoresponse along the OS does not increase linearly with the light intensity as with diffuse light. © 2015, National Academy of Sciences. All rights reserved.
dc.description.sponsorshipWe thank Profs. Trevor Lamb and Fabio Benfenati for reading the manuscript, M. Lough for checking the English, and Paolo Fabris for MatLab support. This work was supported by FOCUS Contract 270483 (FP7-ICT-2009-6) from the European Union.
dc.publisherProceedings of the National Academy of Sciences
dc.relation.urlhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443333
dc.subjectCGMP diffusion
dc.subjectOptical fiber
dc.subjectPhosphodiesterase
dc.subjectPhototransduction
dc.subjectRhodopsin
dc.titleThe phototransduction machinery in the rod outer segment has a strong efficacy gradient
dc.typeArticle
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalProceedings of the National Academy of Sciences
dc.identifier.pmcidPMC4443333
dc.contributor.institutionInternational School for Advanced Studies, Trieste, Italy
dc.contributor.institutionCluster in Biomedicine S.c.r.l, Trieste, Italy
dc.contributor.institutionIstituto Italiano di Tecnologia, Genova, Italy
dc.contributor.institutionRapp OptoElectronic, Wedel, Germany
dc.contributor.institutionBio-Nanotechnology and Engineering for Medicine, Department of Experimental and Clinical Medicine, University of Magna Graecia, Catanzaro, Italy
dc.contributor.institutionIstituto Officina dei Materiali, Consiglio Nazionale Delle Ricerche, Trieste, Italy
dc.contributor.institutionDepartment of Electrical Engineering, Division of Automatic Control, Linkoping University, Linkoping, Sweden
kaust.personDi Fabrizio, Enzo M.
dc.date.published-online2015-05-04
dc.date.published-print2015-05-19


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