Retina cell types

The retinol that is delivered to the retinas of the eyes in this manner is accumulated by rod and cone cells. In the rods (which are the better characterized of the two cell types), retinol is oxidized by a specific retinol dehydrogenase to become 2iW-trans retinal and then converted to 11-eis retinal by reti-... 

Raff I remember Harris Hartenstein (1991) did an experiment in which they used hydroxyurea to block cell proliferation in the Nenopus retina. They showed that all the different cell types still developed. This same type of result has been seen in other systems. 

Altogether, there are many unknowns about carotenoid transport in the retina. However, present knowledge on carotenoid uptake in other cell types and the finding of multiple proteins potentially involved in carotenoid transport in the RPE and adjacent neural retina leads to the suggestion that several hypothetical pathways exist (Figure 15.3). Many such pathways can be easily tested in cultured RPE. 

As mentioned previously, the ability of carotenoids to inhibit oxidative stress was tested in vitro in many different cell types. In the retina only lutein and zeaxanthin accumulate in sufficient concentrations to exert direct antioxidant effects, therefore our further discussion of these antioxidant effects will be focused mainly on those two xanthophylls. 

The more subtle roles of different PMCAs in cardiac and sperm function, synaptic signaling in retina and hippocampus, etc. suggest that these are not housekeeping genes, rather they provide an important function in many cell types and tissues. It seems likely that changes in each of the PMCA isoforms may contribute quantitatively to a number of complex diseases in ways yet to be discovered. 

Dacey DM, Lee BB.The blue-on opponent pathway in primate retina originates from a distinct bistratified ganglion cell type. Nature 1994 367 731-735. 

Dacey DM, Packer OS. Colour coding in the primate retina diverse cell types and cone-specific circuitry. Curr Opin Neurobiol 2003 13 421-427. 

In addition to the neuronal cell types responsible for visual signal transmission the retina has several types of supporting cells, similar in function to the RPE cells supporting the photoreceptor outer segments. The most important of these are the Mueller cells, whose principal role appears to be to buffer and balance electrolyte concentrations in the extracellular space, in response to the activity of the retinal neurons, especially photoreceptors. 

Wliich of the following is the predominant glial cell type in the retina ... 

Photoreception in the eye is the function of two specialized cell types located in the retina the rod and cone cells. Rod cells are sensitive and fxmction in dim illumination, are concentrated around the periphery of the retina are about 100 million cells. 

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