Michaela Bitzer

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PURPOSE Imposing defocus to the retina results in compensatory changes of axial eye growth. It is not clear which factors initially contribute to this process and whether they act on the post-translational, translational, or transcriptional level. We have measured early changes in mRNA levels, in response to imposed negative and positive defocus, of the(More)
PURPOSE To characterize the visual stimuli that control the expression of the transcription factor ZENK in glucagon-immunoreactive amacrine cells of the chicken retina. ZENK was previously found to change in correlation with the sign (+ or -) of imposed defocus, making it a potential candidate for regulation of the synthesis of growth factors involved in(More)
Eye growth is visually regulated via messengers that are released from the retina. The retina involves a yet unknown algorithm to analyse the projected image so that the appropriate growth rates for the back of the eye are ensured. One biochemical candidate that could act as a growth controller, is retinoic acid (RA). Previous work (Seko, Shimokawa and(More)
Gamma-aminobutyric acid (GABA) is likely expressed in horizontal cells of all species, although conflicting physiological findings have led to considerable controversy regarding its role as a transmitter in the outer retina. This study has evaluated key components of the GABA system in the outer retina of guinea pig, an emerging retinal model system. The(More)
PURPOSE Expression of the transcription factor ZENK in glucagon amacrine cells of the chicken retina is enhanced after treatment with positive spectacle lenses and reduced after treatment with negative lenses. ZENK may, therefore, have an important role in emmetropization. To learn more about its regulation, we have studied its expression after retinal(More)
Muscarinic antagonists, particularly atropine, can inhibit myopia development in several animal models and also in children. However, the biochemical basis of the inhibition of axial eye growth remains obscure, and there are doubts whether muscarinic receptors are involved at all. Experiments in chickens and monkeys have shown that the synthesis of the(More)
PURPOSE The transcription factor ZENK, expressed in glucagon amacrine cells in the retina in the chicken, has been shown to respond selectively to the sign of imposed defocus. To find out whether the retina by itself is able to perform the underlying image processing, we used ZENK to probe responses of amacrine cells to defined amounts of imposed defocus,(More)
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