Development of visual cells in the toadBufo melanostictus (Schneider)

1990 ◽  
Vol 99 (6) ◽  
pp. 419-429
Author(s):  
Sultana Niazi ◽  
I A Niazi
Keyword(s):  
Visual Cells

Ultrastructural Changes of Smoooth Endoplasmic Reticulum in the Retinal Pigment Epithelium by Choline Chloride

1972 ◽  
Vol 30 ◽  
pp. 58-59
Author(s):  
Kazushige Hirosawa ◽  
Eichi Yamada
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cell ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Choline Chloride ◽  
Retinal Pigment ◽  
Ultrastructural Changes ◽  
Lower Vertebrate ◽  
Visual Cells ◽  
Pigment Epithelial

The pigment epithelium is located between the choriocapillary and the visual cells. The pigment epithelial cell is characterized by a large amount of the smooth endoplasmic reticulum (SER) in its cytoplasm. In addition, the pigment epithelial cell of some lower vertebrate has myeloid body as a specialized form of the SER. Generally, SER is supposed to work in the lipid metabolism. However, the functions of abundant SER and myeloid body in the pigment epithelial cell are still in question. This paper reports an attempt, to depict the functions of these organelles in the frog retina by administering one of phospholipid precursors.

Inositol-1,4,5-trisphosphate-binding proteins controlling the phototransduction cascade of invertebrate visual cells

2001 ◽  
Vol 204 (3) ◽  
pp. 487-493
Author(s):  
A. Kishigami ◽  
T. Ogasawara ◽  
Y. Watanabe ◽  
M. Hirata ◽  
T. Maeda ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Binding Proteins ◽  
Affinity Column ◽  
Receptor Kinase ◽  
Nucleotide Exchange ◽  
Visual Cells ◽  
Signal Cascade ◽  
Phosphatidylinositol Turnover ◽  
Inositol 1,4,5 Trisphosphate ◽  
Phototransduction Cascade

The main phototransduction cascade in invertebrate visual cells involves the turnover of phosphatidylinositol, an important biochemical mechanism common to many signal-transduction systems. Light-activated rhodopsin stimulates guanine nucleotide exchange on the Gq class of G-protein, which activates phospholipase C to hydrolyze phosphatidylinositol 4,5-bisphosphate to inositol-1,4,5-trisphosphate and diacylglycerol. Subsequently, inositol-1,4,5-trisphosphate-binding proteins continue the signal cascade. Here, we report on the first inositol-1,4,5-trisphosphate-binding proteins demonstrated in an invertebrate visual system with our investigation of the photosensitive rhabdoms of squid. We screened the ability of proteins to interact with inositol-1,4,5-trisphosphate by affinity column chromatography with an inositol-1,4,5-trisphosphate analogue. We detected an inositol-1,4,5-trisphosphate-binding affinity in phospholipase C, receptor kinase and five other proteins in the cytosolic fraction and, surprisingly, rhodopsin in the membrane fraction. A binding assay with (3)H-labelled inositol-1,4,5-trisphosphate demonstrated the inositol-1,4,5-trisphosphate affinity of each of the purified proteins. Since rhodopsin, receptor kinase and phospholipase C are involved upstream of phosphatidylinositol turnover in the signal cascade, our result suggests that phosphatidylinositol turnover is important in feedback pathways in the signalling system.

Neuronal activity related to visually guided saccades in the frontal eye fields of rhesus monkeys: comparison with supplementary eye fields

1991 ◽  
Vol 66 (2) ◽  
pp. 559-579 ◽  
Author(s):  
J. D. Schall
Keyword(s):  
Rhesus Monkeys ◽  
Time Course ◽  
Receptive Fields ◽  
Peak Level ◽  
Frontal Eye Fields ◽  
Visually Guided ◽  
Visual Cells ◽  
Preparatory Set ◽  
Functional Classes ◽  
Supplementary Eye Fields

1. The purpose of this study was to analyze the response properties of neurons in the frontal eye fields (FEF) of rhesus monkeys (Macaca mulatta) and to compare and contrast the various functional classes with those recorded in the supplementary eye fields (SEF) of the same animals performing the same go/no-go visual tracking task. Three hundred ten cells recorded in FEF provided the data for this investigation. 2. Visual cells in FEF responded to the stimuli that guided the eye movements. The visual cells in FEF responded with a slightly shorter latency and were more consistent and phasic in their activation than their counterparts in SEF. The receptive fields tended to emphasize the contralateral hemifield to the same extent as those observed in SEF visual cells. 3. Preparatory set cells began to discharge after the presentation of the target and ceased firing before the saccade, after the go/no-go cue was given. These neurons comprised a smaller proportion in FEF than in SEF. In contrast to their counterparts in SEF, the preparatory set cells in FEF did not respond preferentially in relation to contralateral movements, even though most responded preferentially for movements in one particular direction. The time course of the discharge of the FEF set cells was similar to that of their SEF counterparts, except that they reached their peak level of activation sooner. The few preparatory set cells in FEF tested with both auditory and visual stimuli tended to respond preferentially to the visual targets, whereas, in contrast, most set cells in SEF were bimodal. 4. Sensory-movement cells represented the largest population of cells recorded in FEF, responding in relation to both the presentation of the targets and the execution of the saccade. Although some of these sensory-movement cells resembled their counterparts in SEF by exhibiting a sustained elevation of activity, most of the FEF sensory-movement cells gave two discrete bursts, one after the presentation of the target and another before and during the saccade. Like their counterparts in SEF, the sensory-movement cells tended to be tuned for saccades into the contralateral hemifield, but this tendency was more pronounced in FEF than in SEF. The FEF sensory-movement cells discharged more briskly, with a shorter latency relative to the presentation of the target, than their counterparts in SEF. In addition, the FEF sensory-movement neurons reached their peak activation sooner than SEF sensory-movement neurons. Most FEF sensory-movement cells exhibited different patterns of activation in response to visual and auditory targets.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Spectral Sensitivity of Single Visual Cells

Nature ◽  
1961 ◽  
Vol 190 (4776) ◽  
pp. 639-639 ◽  
Author(s):  
H. AUTRUM ◽  
D. BURKHARDT
Keyword(s):  
Spectral Sensitivity ◽  
Visual Cells

Electrophysiological measurements of spectral sensitivity of central visual cells in eye of blowfly

Nature ◽  
1976 ◽  
Vol 260 (5549) ◽  
pp. 342-344 ◽  
Author(s):  
PETER MEFFERT ◽  
ULRICH SMOLA
Keyword(s):  
Spectral Sensitivity ◽  
Visual Cells ◽  
Electrophysiological Measurements

scholarly journals Molecular Mechanism of Transduction in Visual Cells

1982 ◽  
Vol 22 (2) ◽  
pp. 70-80 ◽  
Author(s):  
Motoyuki TSUDA
Keyword(s):  
Molecular Mechanism ◽  
Visual Cells

The Question of Relationship Between Golgi Vesicles and Synaptic Vesicles in Octopus Neurons

1970 ◽  
Vol 7 (1) ◽  
pp. 189-201
Author(s):  
E. G. GRAY
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Frontal Lobe ◽  
Synaptic Vesicles ◽  
Optic Lobe ◽  
Visual Cell ◽  
Visual Cells ◽  
Golgi Vesicles

Electron microscopy of the vertical lobe of octopus brain shows that the synaptic knobs of axons with perikarya in the median superior frontal lobe have synaptic vesicles, approximately 28% of which are dense-cored (or granulated). In contrast, the endings of the amacrine neurons in the vertical lobe and the endings in the retina and optic lobe, both of which are derived from the retinal visual cells, have only agranular synaptic vesicles. The Golgi apparatuses of the median superior frontal perikarya have vesicles, approximately 4.3% of which are granulated. The amacrine Golgi apparatuses have 1.5% granulated vesicles. The visual cell Golgi apparatuses have virtually no dense-cored vesicles, only agranular ones. The question of the formation of dense-cored and agranular synaptic vesicles at the Golgi apparatus and their subsequent transport to the terminals are related to these observations.

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