English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Biochemical and molecular characterization of the sodium-calcium exchanger from bovine rod photoreceptors

MPS-Authors
/persons/resource/persons253262

Achilles,  Anita
Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society;

/persons/resource/persons252691

Friedel,  Ute
Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society;

/persons/resource/persons137691

Haase,  Winfried
Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society;

/persons/resource/persons137849

Reiländer,  Helmut
Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society;

/persons/resource/persons252599

Cook,  Neil J.
Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Achilles, A., Friedel, U., Haase, W., Reiländer, H., & Cook, N. J. (1991). Biochemical and molecular characterization of the sodium-calcium exchanger from bovine rod photoreceptors. Annals of the New York Academy of Sciences, 639(1), 234-244. doi:10.1111/j.1749-6632.1991.tb17310.x.


Cite as: http://hdl.handle.net/21.11116/0000-0007-B2AB-F
Abstract
Vertebrate rod photoreceptors hyperpolarize in response to light by means of the closure of cGMP-gated channels, present in the plasma membrane of the outer segment, which mediate an inwardly directed cation flow referred to as the dark current. Although these channels are most permeable to monovalent cations, they also exhibit an appreciable permeability to the divalent cations Ca2+ and Mg2+. Indeed, calcium ions entering the cell via the cGMP-gated channel constitute 10-15% of the dark current. The sodium-calcium exchanger of rod photoreceptors is responsible for the extrusion of calcium ions entering the outer segment cytosol through the cGMP-gated channel under conditions of darkness. The driving force for this calcium extrusion process is an inwardly directed electrochemical Na+ gradient together with an out wardly directed electrochemical K+ gradient. The stoichiometry of the exchange process under physiological conditions is now accepted to be 4 Nao+: 1 Cai2+ + 1 Ki and is therefore electrogenic.