A cyclic adenosine monophosphate agonist elevates the b- and c-waves of the rabbit direct-current electroretinogram

Bragadóttir, Ragnheiður; Jarkman, Sven

doi:10.1007/bf01203864

Cited by 5 publications

(2 citation statements)

References 25 publications

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“…There is evidence that cAMP signaling contributes to both ON and OFF cone bipolar cell signaling (Bragadottir and Jarkman, 1995, Maguire and Werblin, 1994). Immunohistochemical evidence demonstrated that PKA type II is selectively localized to a subtype of cone bipolar cells, type 3b, whereas HCN4 selectively labeled type 3a cone bipolar cells (Mataruga et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Differential distribution of exchange proteins directly activated by cyclic AMP within the adult rat retina

Whitaker

Cooper

2010

Neuroscience

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The recently discovered exchange protein directly activated by cAMP (Epac), a guanine exchange factor for the G-protein RAP-1, is directly activated by cAMP independently of PKA. While cAMP is known to be an important second messenger in the retina, the presence of Epac has not been investigated in this tissue. The goal of the present study was to determine if the Epac1 and Epac2 genes are present and to characterize their location within the retina. Western blot analysis revealed that Epac1 and Epac2 proteins are expressed within the retina, and the presence of mRNA was demonstrated with the aid of RT-PCR. Additionally, we used immunofluorescence and confocal microscopy to demonstrate that Epac1 and Epac2 have overlapping as well as unique distributions within the retina. Both are present within horizontal cells, rod and cone bipolar cells, cholinergic amacrine cells, retrograde labeled retinal ganglion cells, and Müller cells. Uniquely, Epac2 was expressed by cone photoreceptor inner and outer segments, cell bodies, and synaptic terminals. In contrast, Epac1 was expressed in VGlut1 and CtBP2 positive photoreceptor synaptic terminals. Together, these results provide evidence that Epac1 and Epac2 are differentially expressed within the retina and provide the framework for further functional studies of cAMP pathways within the retina.

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Section: Discussionmentioning

confidence: 99%

Differential distribution of exchange proteins directly activated by cyclic AMP within the adult rat retina

Whitaker

Cooper

2010

Neuroscience

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“…Recent studies suggest that some cone bipolar cells, which can be identified using PKA, contribute to the rod driven pathway (Mataruga et al, 2007). There is also evidence that cAMP contributes to both OFF and ON cone pathways (Bragadottir and Jarkman, 1995, Maguire and Werblin, 1994). …”

Section: Discussionmentioning

confidence: 99%

The novel distribution of phosphodiesterase-4 subtypes within the rat retina

Whitaker

Cooper

2009

Neuroscience

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Phosphodiesterases (PDEs) are important regulators of signal transduction processes. While much is known about the function of cyclic GMP specific PDEs in the retina, much less is known about the closely related, cyclic AMP specific PDEs. The purpose of the present study is to characterize and localize PDE4 within the adult rat retina. We have used western blotting, RT-PCR, and immunohistochemistry together with retrograde labeling to determine the presence and location of each PDE4 subtype. Western blot analysis revealed that multiple isoforms of PDE4A, B, and D subtypes are present within the retina, whereas the PDE4C subtype was absent. These data were confirmed by RT-PCR. Using immunohistochemistry we show that all 3 PDE4s are abundantly expressed within the retina where they all colocalize with retrograde-labeled retinal ganglion cells, as well as bipolar cells, horizontal cells, and cholinergic amacrine cells, whereas Müller cells lack PDE4 expression. Uniquely, PDE4B was expressed by the inner and outer segments of rod photoreceptors as well as their terminals within the outer plexiform layer. Collectively, our results demonstrate that PDE4s are abundantly expressed throughout the rodent retina and this study provides the framework for further functional studies. KeywordscAMP; Rolipram; PDE4; PKA; immunohistochemistry; retrograde Cyclic nucleotide second messengers are vital for signaling within the retina. The importance of cGMP signaling is well established within the first stages of visual transduction, however less is known about cAMP signaling. Many events that take place in the retina both developmentally and in the adult retina are dependent upon the second messenger cAMP. For example, cAMP plays a role in synaptogenesis (Firth et al., 2005, Stellwagen et al., 1999, post-synaptic transmission (Blazynski, 1987, Brown and Makman, 1972, Osborne, 1991, Reppert et al., 1995, Van Buskirk and Dowling, 1981, and electrical communication between Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2010 November 10. Published in final edited form as:Neuroscience. (Urschel et al., 2006). This indicates the need for tight regulation of this ubiquitous second messenger.To better understand the roles of cAMP within the retina we must focus on the cellular sites of cAMP regulation which include production and hydrolysis. Production of cAMP is solely accomplished by the activity of adenylate cyclases, whereas hydrolysis requires the activity of phosphodiesterases. Adenylate cyclases con...

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Electroretinographic oscillatory potentials are reduced in adenylyl cyclase type I deficient mice

2002

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Electroretinography (ERG) of adult Adcy1(brl) mutant mice, which are deficient in adenylyl cyclase type 1 (AC1) activity, revealed decreased amplitude of the oscillatory potentials (OP) and of the primary rising phase of the b-wave intensity-response function in scotopic conditions. These abnormalities were less discernable in 3-6 week old mutants. No abnormalities were detected in the ERG signal obtained in photopic conditions or in the dark adaptation dynamics. The mutants displayed no histologic evidence of retinal degeneration. Retinal output, as measured by visual evoked potentials, was not different from heterozygous control mice. AC1-dependent pathways contribute to the generation of the retinal response to light. They may be necessary for the maintenance of the neural generators of the ERG OP.

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A cyclic adenosine monophosphate agonist elevates the b- and c-waves of the rabbit direct-current electroretinogram

Cited by 5 publications

References 25 publications

Differential distribution of exchange proteins directly activated by cyclic AMP within the adult rat retina

Differential distribution of exchange proteins directly activated by cyclic AMP within the adult rat retina

The novel distribution of phosphodiesterase-4 subtypes within the rat retina

Electroretinographic oscillatory potentials are reduced in adenylyl cyclase type I deficient mice

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