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Mutations in rod opsin, the visual pigment protein of rod photoreceptors, account for approximately 15% of all inherited human retinal degenerations. However, the physiological and molecular events underlying the disease process are not well understood. One approach to this question has been to study transgenic mice expressing opsin genes containing defined(More)
The four spectral cone types in the zebrafish retina each contribute to photopic visual sensitivity as measured by the b-wave of the electroretinogram (ERG). The goal of the current study was to evaluate a model of photopic b-wave spectral sensitivity in the zebrafish that mapped first-order cellular and biophysical aspects of cone photoreceptors (visual(More)
The retinas of adult teleost fish can regenerate neurons following a chemical or mechanical injury. Previous studies have demonstrated that mechanical excision of fish retina induces a hyperplasia within the retinal sheet, including the formation of a proliferative blastema from whence new retinal cells are produced to fill the excision site. The current(More)
In part because of its laminar organization and morphologically distinct cell populations, the vertebrate retina has often been used as a system for investigating the assembly of neural structures. The retinas of adult teleost fish, because they grow throughout life and can regenerate following an injury, provide an especially attractive model system for(More)
Rods and cones contain closely related but distinct G protein-coupled receptors, opsins, which have diverged to meet the differing requirements of night and day vision. Here, we provide evidence for an exception to that rule. Results from immunohistochemistry, spectrophotometry, and single-cell RT-PCR demonstrate that, in the tiger salamander, the green(More)
The mechanisms that control cellular pattern formation in the growing vertebrate central nervous system are poorly understood. In an effort to reveal mechanistic rules of cellular pattern formation in the central nervous system, quantitative spatial analysis and computational modeling techniques were applied to cellular patterns in the inner retina of the(More)
The vertebrate retina is composed of cellular arrays that are nonrandom across two-dimensional space. The determinants of these nonrandom two-dimensional cellular patterns in the inner nuclear layer of the retina were investigated using empirical and computational modeling techniques. In normal and experimental models of goldfish retinal growth, the(More)
PURPOSE Investigate the effects of systemic hypothyroidism upon the differentiated, growing, and regenerating retina of postmetamorphic winter flounder, a vertebrate that experiences a thyroid hormone (TH) induced metamorphosis during development. METHODS A loss-of-signal strategy was utilized in which TH signaling was disrupted by inhibiting TH(More)
PURPOSE Accumulation of free opsin by mutations in rhodopsin or insufficiencies in the visual cycle can lead to retinal degeneration. Free opsin activates phototransduction; however, the link between constitutive activation and retinal degeneration is unclear. In this study, the photoresponses of Xenopus rods rendered constitutively active by vitamin A(More)
Stress-induced alterations in expression of c-fos protein (Fos) in mesencephalic dopamine (DA) neurons of the rat were examined in order to discern which midbrain DA neurons are metabolically activated by stress. Restraint stress for 30 min increased the number of DA neurons exhibiting Fos-like immunoreactivity in the ventral tegmental area (VTA), but not(More)