The phototransduction machinery in the rod outer segment has a strong efficacy gradient

Handle URI:
http://hdl.handle.net/10754/564170
Title:
The phototransduction machinery in the rod outer segment has a strong efficacy gradient
Authors:
Mazzolini, Monica; Facchetti, Giuseppe; Andolfi, Laura; Zaccaria, Remo Proietti; Tuccio, Salvatore; Treud, Johannes; Altafini, Claudio; Di Fabrizio, Enzo M. ( 0000-0001-5886-4678 ) ; Lazzarino, Marco; Rapp, Gert; Torre, Vincent
Abstract:
Rod 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.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program
Publisher:
Proceedings of the National Academy of Sciences
Journal:
Proceedings of the National Academy of Sciences
Issue Date:
4-May-2015
DOI:
10.1073/pnas.1423162112
PubMed ID:
25941368
PubMed Central ID:
PMC4443333
Type:
Article
ISSN:
00278424
Sponsors:
We 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.
Additional Links:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443333
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorMazzolini, Monicaen
dc.contributor.authorFacchetti, Giuseppeen
dc.contributor.authorAndolfi, Lauraen
dc.contributor.authorZaccaria, Remo Proiettien
dc.contributor.authorTuccio, Salvatoreen
dc.contributor.authorTreud, Johannesen
dc.contributor.authorAltafini, Claudioen
dc.contributor.authorDi Fabrizio, Enzo M.en
dc.contributor.authorLazzarino, Marcoen
dc.contributor.authorRapp, Gerten
dc.contributor.authorTorre, Vincenten
dc.date.accessioned2015-08-03T12:34:57Zen
dc.date.available2015-08-03T12:34:57Zen
dc.date.issued2015-05-04en
dc.identifier.issn00278424en
dc.identifier.pmid25941368en
dc.identifier.doi10.1073/pnas.1423162112en
dc.identifier.urihttp://hdl.handle.net/10754/564170en
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.en
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.en
dc.publisherProceedings of the National Academy of Sciencesen
dc.relation.urlhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443333en
dc.subjectCGMP diffusionen
dc.subjectOptical fiberen
dc.subjectPhosphodiesteraseen
dc.subjectPhototransductionen
dc.subjectRhodopsinen
dc.titleThe phototransduction machinery in the rod outer segment has a strong efficacy gradienten
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalProceedings of the National Academy of Sciencesen
dc.identifier.pmcidPMC4443333en
dc.contributor.institutionInternational School for Advanced Studies, Trieste, Italyen
dc.contributor.institutionCluster in Biomedicine S.c.r.l, Trieste, Italyen
dc.contributor.institutionIstituto Italiano di Tecnologia, Genova, Italyen
dc.contributor.institutionRapp OptoElectronic, Wedel, Germanyen
dc.contributor.institutionBio-Nanotechnology and Engineering for Medicine, Department of Experimental and Clinical Medicine, University of Magna Graecia, Catanzaro, Italyen
dc.contributor.institutionIstituto Officina dei Materiali, Consiglio Nazionale Delle Ricerche, Trieste, Italyen
dc.contributor.institutionDepartment of Electrical Engineering, Division of Automatic Control, Linkoping University, Linkoping, Swedenen
kaust.authorDi Fabrizio, Enzo M.en

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