Patch electrode recording of currents from the plasma membrane of rod outer segments of the frog

1982 ◽  
Vol 394 (S1) ◽  
pp. R45-R45 ◽  
Author(s):  
G. Nöll ◽  
E. Neher ◽  
Ch Baumann
Keyword(s):  
Plasma Membrane ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Electrode Recording

scholarly journals MEMBRANE CHARACTERISTICS AND OSMOTIC BEHAVIOR OF ISOLATED ROD OUTER SEGMENTS

1973 ◽  
Vol 56 (2) ◽  
pp. 389-398 ◽  
Author(s):  
Juan I. Korenbrot ◽  
Dennis T. Brown ◽  
Richard A. Cone
Keyword(s):  
Plasma Membrane ◽  
Outer Segment ◽  
Receptor Cell ◽  
Water Flux ◽  
Rod Outer Segments ◽  
Repeat Distance ◽  
Permeability Constant ◽  
Outer Segments ◽  
Length Reduction ◽  
Osmotic Behavior

Freshly isolated frog rod outer segments are sensitive osmometers which retain their photosensitivity; their osmotic behavior reveals essentially the same light-sensitive Na+ influx observed electrophysiologically in the intact receptor cell. Using appropriate osmotic conditions we have examined freeze-etch replicas of freshly isolated outer segments to identify the membrane which regulates the flow of water and ions. Under isosmotic conditions we find that the disc to disc repeat distance is almost exactly twice the thickness of a disc. This ratio appears to be the same in a variety of vertebrate rod outer segments and can be reliably measured in freeze-etch images. Under all our osmotic conditions the discs appear nearly collapsed. However, when the length of the outer segment is reduced by hyperosmotic shocks the discs move closer together. This markedly reduces the ratio of repeat distance to disc thickness since disc thickness remains essentially constant. Thus, the length reduction of isolated outer segments after hyperosmotic shocks primarily results from reduction of the extradisc volume. Since the discs are free floating and since they undergo negligibly small changes in volume, the plasma membrane alone must be primarily responsible for regulating the water flux and the light-sensitive Na+ influx in freshly isolated outer segments. On this basis we calculate, from the osmotic behavior, that the plasma membrane of frog rod outer segment has a Na+ permeability constant of about 2.8 x 10-6 cm/s and an osmotic permeability coefficient of greater than 2 x 10-3 cm/s.

Letter to the editor: Squalene is Localized to the Plasma Membrane in Bovine Retinal Rod Outer Segments

1997 ◽  
Vol 64 (2) ◽  
pp. 279-282 ◽  
Author(s):  
STEVEN J. FLIESLER ◽  
KATHLEEN BOESZE-BATTAGLIA ◽  
ZOPHIA PAW ◽  
R.KENNEDY KELLER ◽  
ARLENE D. ALBERT
Keyword(s):  
Plasma Membrane ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Letter To The Editor ◽  
Retinal Rod ◽  
Retinal Rod Outer Segments

scholarly journals Localization of peripherin/rds in the disk membranes of cone and rod photoreceptors: relationship to disk membrane morphogenesis and retinal degeneration.

1992 ◽  
Vol 116 (3) ◽  
pp. 659-667 ◽  
Author(s):  
K Arikawa ◽  
L L Molday ◽  
R S Molday ◽  
D S Williams
Keyword(s):  
Plasma Membrane ◽  
Retinal Degeneration ◽  
Outer Segment ◽  
Photoreceptor Cells ◽  
Growth Stages ◽  
Rod Outer Segments ◽  
Rod Photoreceptor ◽  
Outer Segments ◽  
Disk Membrane ◽  
Membrane Morphogenesis

The outer segments of vertebrate rod photoreceptor cells consist of an ordered stack of membrane disks, which, except for a few nascent disks at the base of the outer segment, is surrounded by a separate plasma membrane. Previous studies indicate that the protein, peripherin or peripherin/rds, is localized along the rim of mature disks of rod outer segments. A mutation in the gene for this protein has been reported to be responsible for retinal degeneration in the rds mouse. In the present study, we have shown by immunogold labeling of rat and ground squirrel retinas that peripherin/rds is present in the disk rims of cone outer segments as well as rod outer segments. Additionally, in the basal regions of rod and cone outer segments, where disk morphogenesis occurs, we have found that the distribution of peripherin/rds is restricted to a region that is adjacent to the cilium. Extension of its distribution from the cilium coincides with the formation of the disk rim. These results support the model of disk membrane morphogenesis that predicts rim formation to be a second stage of growth, after the first stage in which the ciliary plasma membrane evaginates to form open nascent disks. The results also indicate how the proteins of the outer segment plasma membrane and the disk membranes are sorted into their separate domains: different sets of proteins may be incorporated into membrane outgrowths during different growth stages of disk morphogenesis. Finally, the presence of peripherin/rds protein in both cone and rod outer segment disks, together with the phenotype of the rds mouse, which is characterized by the failure of both rod and cone outer segment formation, suggest that the same rds gene is expressed in both types of photoreceptor cells.

Ca2+ influx into bovine retinal rod outer segments mediated by Na+/Ca2+/K+ exchange

1995 ◽  
Vol 269 (5) ◽  
pp. C1153-C1159 ◽  
Author(s):  
P. P. Schnetkamp ◽  
J. E. Tucker ◽  
R. T. Szerencsei
Keyword(s):  
Plasma Membrane ◽  
Light Adaptation ◽  
Rod Outer Segments ◽  
Site Model ◽  
Outer Segments ◽  
Retinal Rod ◽  
Absolute Requirement ◽  
Previous Loading ◽  
Retinal Rod Outer Segments ◽  
Ionophore Monensin

Ca(2+)-depleted rod outer segments (ROS) were purified from bovine retinal rod photoreceptors, and factors influencing Ca2+ influx into ROS via the plasma membrane Na+/Ca2+/K+ exchanger were analyzed. Intracellular alkali cation concentrations were manipulated by 1) previous loading via the ionophore monensin followed by removal of monensin and 2) addition of the channel ionophore gramicidin during Ca(2+)-influx measurements. Ca2+ influx was measured as a rise in cytosolic free Ca2+ with the Ca(2+)-indicating dye fluo 3. An absolute requirement for intracellular Na+ was observed with a Na+ dissociation constant of 30-40 mM, whereas intracellular K+ was a potent inhibitor of Ca2+ influx, apparently by competing with Na+ for a common site on the Na+/Ca2+/K+ exchanger. Half-maximal Ca2+ influx was observed at an external free Ca2+ concentration of 0.9 microM when no external Na+ was present and 3.5 microM when 10 mM external Na+ was present. Our observations are discussed in the context of 1) a three-site model for the Na+/Ca2+/K+ exchanger and 2) earlier experiments on light adaptation in rods, which depended on minimizing Ca2+ fluxes across the ROS plasma membrane.

Microtubules in a rod-specific cytoskeleton associated with outer segment incisures

2000 ◽  
Vol 17 (5) ◽  
pp. 711-722 ◽  
Author(s):  
MARION SANGSTER ECKMILLER
Keyword(s):  
Plasma Membrane ◽  
Electron Microscopic Examination ◽  
Normal Structure ◽  
Rod Outer Segments ◽  
Electron Microscopic ◽  
Immunofluorescent Localization ◽  
Rods And Cones ◽  
Retinal Degenerations ◽  
Outer Segments ◽  
Tubulin Immunofluorescence

In many vertebrate retinas the outer segments of rod photoreceptors have multiple incisures, that is, there are numerous indentations in the highly curved membrane forming the edge of their disks and in the plasma membrane enclosing the entire stack of disks. Immunofluorescent localization of tubulin in amphibian photoreceptors yielded a novel series of thin, parallel, fluorescent lines in rod outer segments that extended their full length and coincided with their multiple incisures. Electron-microscopic examination of amphibian retinas revealed the structures responsible for this fluorescence: longitudinally oriented microtubules were associated with incisures at heights throughout rod outer segments. These microtubules were located between the disk rims and the overlying plasma membrane, in the small cytoplasmic compartment at the mouth of incisures; the microtubules and membranes were separated from each other by distances that were uniform, as though interconnected by filaments described in other studies. Thus, in amphibian rod outer segments the incisures mark the site of a cytoskeletal system containing longitudinal microtubules distinct from those of the ciliary axoneme, linked by filaments to the adjacent membranes. This cytoskeleton is expected to be important for the normal structure, function, and renewal of rod outer segments. In amphibian cone outer segments, which do not have incisures, the only anti-tubulin immunofluorescence and the only microtubules were at the axoneme. These findings may help elucidate the diverse properties of rods and cones in many vertebrate retinas and could prove relevant for human retinal degenerations.

scholarly journals Rhodopsin in the rod outer segment plasma membrane.

1976 ◽  
Vol 69 (1) ◽  
pp. 29-42 ◽  
Author(s):  
S Basinger ◽  
D Bok ◽  
M Hall
Keyword(s):  
Plasma Membrane ◽  
Gel Electrophoresis ◽  
Visual Pigment ◽  
Outer Segment ◽  
Gel Filtration ◽  
Acid Mixture ◽  
Rod Outer Segments ◽  
Gel Filtration Chromatography ◽  
Rod Outer Segment ◽  
Outer Segments

Isolated frog retinas were incubated in vitro with a 4-h pulse of [3H]leucine, then chased for 32 h with a nonradioactive amino acid mixture. At the end of the incubation, light and electron microscope autoradiograms were prepared from some of the retinas. The autoradiograms revealed: (a) intense radioactivity in the basal disks of the rod outer segments, (b) diffuse label evenly distributed throughout the rod outer segments, and (c) a high concentration of label in the entire rod outer segment plasma membrane. Incubation under identical conditions, but with puromycin added, significantly inhibited the labeling of all of these components. To identify the labeled proteins, purified outer segments from the remaining retinas were analyzed biochemically by SDS disc gel electrophoresis and gel filtration chromatography. SDS gel electrophoresis showed that about 90% of the total rod outer segment radioactivity chromatographed coincident with visual pigment, suggesting that the radiolabeled protein in the plasma membrane is visual pigment. Gel filtration chromatography demonstrated that the radiolabeled protein co-chromatographed with rhodopsin rather than opsin, and that the newly synthesized visual pigment is both the basal disks and the plasma membrane is present in the native configuration.

Electrical activity of vertebrate photoreceptors

1970 ◽  
Vol 3 (2) ◽  
pp. 179-222 ◽  
Author(s):  
Tsuneo Tomita
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Intracellular Recording ◽  
Rod Outer Segments ◽  
Schematic Diagram ◽  
Intracellular Space ◽  
Double Membrane ◽  
Scotopic Vision ◽  
Rods And Cones ◽  
Outer Segments

It has been known since the time of Schultze (1866) that in the vertebrate retina there are two types of photoreceptors, rods and cones, and that they serve different visual functions; rods for scotopic vision, and cones for photopic. The terminology originates from the shape of the outer segments in which the photosensitive pigment molecules are contained. The cone outer segments are conic and taper towards the tips, while the rod outer segments are typically cylindrical. Fig. 1 is a schematic diagram from Brown, Gibbons & Wald (1963) of the ultrastructure of the rod and cone outer segments of the mudpuppy, Necturus, as studied by electron microscopy. Both appear to be made up of a pile of transverse paired membranes. In cones these arise by infolding of the plasma membrane, and in rods they have probably arisen in a similar way, but each pair of membranes is sealed around the edge so as to form a closed double-membrane disc (Sjöstrand, 1961). Because of the universal lamellation within the rod and cone outer segments, it looks as if there were no appreciable intracellular space, but yet Toyoda, Nosaki & Tomita (1969), and Toyoda et al. (1970) were successful in intracellular recording from the outer segments of single rods of the nocturnal gecko and frog.

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