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We studied the responses of rod photoreceptors that were elicited with light flashes or sinusoidally modulated light by using intracellular recording. Dark-adapted Xenopus rod photoreceptors responded to sinusoidally modulated green lights at temporal frequencies between 1 Hz and 4 Hz. In normal Ringer's solution, 57% of the rods tested could follow red lights that were matched for equal rod absorbance to frequencies >5 Hz, indicating an input from red-sensitive cones. Quinpirole (10 microM), a D2 dopamine agonist, increased rod-cone coupling, whereas spiperone (5 microM), a selective D2 antagonist, completely suppressed it. D1 dopamine ligands were without effect. Neurobiotin that was injected into single rods diffused into neighboring rods and cones in quinpirole-treated retinas but only diffused into rods in spiperone-treated retinas. A subpopulation of rods (ca. 10% total rods) received a very strong cone input, which quickened the kinetics of their responses to red flashes and greatly increased the bandpass of their responses to sinusoidally modulated light. Based on electron microscopic examination, which showed that rod-rod and cone-cone gap junctions are common, whereas rod-cone junctions are relatively rare, we postulate that cone signals enter the rod network through a minority of rods with strong cone connections, from which the cone signal is further distributed in the rod network. A semiquantitative model of coupling, based on measures of gap-junction size and distribution and estimates of their conductance and open times, provides support for this assumption. The same network would permit rod signals to reach cones.
Akopian,
D2 dopamine receptor-mediated inhibition of a hyperpolarization-activated current in rod photoreceptors.
1996, Pubmed,
Xenbase
Akopian,
D2 dopamine receptor-mediated inhibition of a hyperpolarization-activated current in rod photoreceptors.
1996,
Pubmed
,
Xenbase
Attwell,
A sign-reversing pathway from rods to double and single cones in the retina of the tiger salamander.
1983,
Pubmed
Ayoub,
Application of a fluorometric method to measure glutamate release from single retinal photoreceptors.
1991,
Pubmed
Baylor,
Location and function of voltage-sensitive conductances in retinal rods of the salamander, Ambystoma tigrinum.
1984,
Pubmed
Bennett,
Gap junctions as electrical synapses.
1997,
Pubmed
Boatright,
Stimulation of endogenous dopamine release and metabolism in amphibian retina by light- and K+-evoked depolarization.
1989,
Pubmed
,
Xenbase
Cohen,
Photoreceptors of mouse retinas possess D4 receptors coupled to adenylate cyclase.
1992,
Pubmed
Copenhagen,
Functional characteristics of lateral interactions between rods in the retina of the snapping turtle.
1976,
Pubmed
Dearry,
D2 dopamine receptors in the human retina: cloning of cDNA and localization of mRNA.
1991,
Pubmed
DeVries,
An alternative pathway for signal flow from rod photoreceptors to ganglion cells in mammalian retina.
1995,
Pubmed
Engbretson,
Rod sensitivity and visual pigment concentration in Xenopus.
1978,
Pubmed
,
Xenbase
Fain,
Sensitivity of toad rods: Dependence on wave-length and background illumination.
1976,
Pubmed
Fain,
Receptor coupling in the toad retina.
1976,
Pubmed
Gold,
Photoreceptor coupling in retina of the toad, Bufo marinus. I. Anatomy.
1979,
Pubmed
Gold,
Photoreceptor coupling in retina of the toad, Bufo marinus. II. Physiology.
1979,
Pubmed
HAEGGENDAL,
IDENTIFICATION AND CELLULAR LOCALIZATION OF THE CATECHOLAMINES IN THE RETINA AND THE CHOROID OF THE RABBIT.
1965,
Pubmed
Hare,
Morphology of physiologically identified bipolar cells in the retina of the tiger salamander, Ambystoma tigrinum.
1986,
Pubmed
Iuvone,
Evidence for a D2 dopamine receptor in frog retina that decreases cyclic AMP accumulation and serotonin N-acetyltransferase activity.
1986,
Pubmed
,
Xenbase
Krizaj,
The effects of L-glutamate, AMPA, quisqualate, and kainate on retinal horizontal cells depend on adaptational state: implications for rod-cone interactions.
1994,
Pubmed
,
Xenbase
Lasansky,
Organization of the outer synaptic layer in the retina of the larval tiger salamander.
1973,
Pubmed
Lasater,
Dopamine decreases conductance of the electrical junctions between cultured retinal horizontal cells.
1985,
Pubmed
McMahon,
Modulation of gap-junction channel gating at zebrafish retinal electrical synapses.
1994,
Pubmed
Muresan,
D2-like dopamine receptors in amphibian retina: localization with fluorescent ligands.
1993,
Pubmed
,
Xenbase
Nagy,
A freeze-fracture study of synaptogenesis in the distal retina of larval Xenopus.
1981,
Pubmed
,
Xenbase
Nelson,
Cat cones have rod input: a comparison of the response properties of cones and horizontal cell bodies in the retina of the cat.
1977,
Pubmed
Normann,
Signal transmission from red cones to horizontal cells in the turtle retina.
1979,
Pubmed
Piccolino,
Decrease of gap junction permeability induced by dopamine and cyclic adenosine 3':5'-monophosphate in horizontal cells of turtle retina.
1984,
Pubmed
Raviola,
Gap junctions between photoreceptor cells in the vertebrate retina.
1973,
Pubmed
Rushton,
Exchange thresholds in dichromats.
1973,
Pubmed
Schmitz,
Glutamate release by the intact light-responsive photoreceptor layer of the Xenopus retina.
1996,
Pubmed
,
Xenbase
Schneeweis,
Photovoltage of rods and cones in the macaque retina.
1995,
Pubmed
Schwartz,
Cones excite rods in the retina of the turtle.
1975,
Pubmed
Torre,
High-pass filtering of small signals by the rod network in the retina of the toad, Bufo marinus.
1983,
Pubmed
Vaney,
Many diverse types of retinal neurons show tracer coupling when injected with biocytin or Neurobiotin.
1991,
Pubmed
Witkovsky,
A microspectrophotometric study of normal and artificial visual pigments in the photoreceptors of Xenopus laevis.
1981,
Pubmed
,
Xenbase
Witkovsky,
Extracellular dopamine concentration in the retina of the clawed frog, Xenopus laevis.
1993,
Pubmed
,
Xenbase
Wu,
Electrical coupling between rods and cones in the tiger salamander retina.
1988,
Pubmed
Yang,
Modulation of rod-cone coupling by light.
1989,
Pubmed
Yau,
Light-induced fluctuations in membrane current of single toad rod outer segments.
1977,
Pubmed
Zhang,
Identification of cone classes in Xenopus retina by immunocytochemistry and staining with lectins and vital dyes.
1994,
Pubmed
,
Xenbase
