title: Cytoplasmic free calcium concentration in dark-adapted retinal rod outer segments.
abstract: We measured the cytoplasmic free Ca concentration in the outer segment of intact, dark-adapted rods of the toad retina. The Ca indicator dye, Quin2, was loaded at concentrations of 0.273 +/- 0.06 mM into the rod cytoplasm by incubation of isolated retinas in the hydrophobic ester, Quin2AM. Quin2 did not alter the cytoplasmic Ca concentration in the dark, but it buffered light-dependent concentration transients and, hence, modified the rod photoresponse. In the presence of 1 mM external Ca, the cytoplasmic Ca concentration in the dark was 273 +/- 129 nM.
authors.affiliation: Department of Physiology, School of Medicine, University of California, San Francisco 94143-0444.
authors.forename: J I
authors.initials: JI
authors.lastname: Korenbrot
authors.forename: D L
authors.initials: DL
authors.lastname: Miller
mesh_terms: D000634:Aminoquinolines / Q000494:pharmacology / Q000633:toxicity; D000814:Aniline Compounds; D000818:Animals; D002024:Bufo marinus; D002118:Calcium / Q000378:metabolism*; D003592:Cytophotometry; D003593:Cytoplasm / Q000378:metabolism*; D003623:Dark Adaptation; D004594:Electrophysiology; D005456:Fluorescent Dyes / Q000494:pharmacology / Q000633:toxicity; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000378:metabolism* / Q000502:physiology; D012160:Retina / Q000502:physiology*; D012374:Rod Cell Outer Segment / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000634:Aminoquinolines; D000814:Aniline Compounds; D005456:Fluorescent Dyes; C063342:ANIS-AM; C035738:Quin2-acetoxymethyl ester; D002118:Calcium