DARPP‐32‐like immunoreactivity in AII amacrine cells of rat retina

Partida, Gloria J.; Lee, Sherwin C.; Haft-Candell, Leah; Nichols, Grant S.; Ishida, Andrew T.

doi:10.1002/cne.20330

Cited by 17 publications

(50 citation statements)

References 85 publications

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“…It is problematic that D1-type receptors have not been found on these cells (Veruki and Wässle, 1996; see also review by Demb and Singer, 2012). On the other hand, DARPP-32 (dopamine and cAMP-regulated phosphoprotein), an important target for dopamine and PKA, is expressed in AII amacrine cells (Partida et al, 2004;Witkovsky et al, 2007), suggesting that the AII could be a target of dopamine in the retina. Second, if D1-type receptor activation drives dephosphorylation of Cx36 in AII amacrines, which mechanisms are then responsible for driving the phosphorylation of Cx36, potentially leading to increased coupling strength?…”

Section: Phosphorylation Of Cx36 In Gap Junctions Between Aii Amacrinesmentioning

confidence: 99%

Electrical synapses between AII amacrine cells in the retina: Function and modulation

Hartveit

Veruki

2012

Brain Research

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Adaptation enables the visual system to operate across a large range of background light intensities. There is evidence that one component of this adaptation is mediated by modulation of gap junctions functioning as electrical synapses, thereby tuning and functionally optimizing specific retinal microcircuits and pathways. The AII amacrine cell is an interneuron found in most mammalian retinas and plays a crucial role for processing visual signals in starlight, twilight and daylight. AII amacrine cells are connected to each other by gap junctions, potentially serving as a substrate for signal averaging and noise reduction, and there is evidence that the strength of electrical coupling is modulated by the level of background light. Whereas there is extensive knowledge concerning the retinal microcircuits that involve the AII amacrine cell, it is less clear which signaling pathways and intracellular transduction mechanisms are involved in modulating the junctional conductance between electrically coupled AII amacrine cells. Here we review the current state of knowledge, with a focus on recent evidence that suggests that the modulatory control involves activity-dependent changes in the phosphorylation of the gap junction channels between AII amacrine cells, potentially linked to their intracellular Ca 2+ dynamics.

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Section: Phosphorylation Of Cx36 In Gap Junctions Between Aii Amacrinesmentioning

confidence: 99%

Electrical synapses between AII amacrine cells in the retina: Function and modulation

Hartveit

Veruki

2012

Brain Research

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“…Protein was isolated as described elsewhere (Partida et al, 2004), with the following modifications to study membrane fraction proteins. After centrifuging the homogenate from twenty retinas at 13000 × g for 15 min at 4 °C, the supernatant was collected and the pellet resuspended in homogenization buffer.…”

Section: Protein Isolation and Western Blot Analysismentioning

confidence: 99%

“…Proteins were transferred to nitrocellulose membranes and probed with antisera as described previously (Partida et al, 2004). Membranes were incubated either in an anti-HCN4 antibody or anti-HCN4 antibody pre-adsorbed with a two-fold higher concentration of control antigen (see the "Antibodies" section below for details), rinsed in TBST, and incubated in secondary antibody conjugated to horseradish peroxidase.…”

Section: Protein Isolation and Western Blot Analysismentioning

confidence: 99%

“…Reagents were obtained from Sigma Chemical (St. Louis, MO), sources listed previously (Partida et al, 2004) …”

Section: Reagentsmentioning

confidence: 99%

“…This fluorophore and that coupled to the dextran were selected because their excitation and emission wavelengths produced minimal cross-contamination during our attempts to stain retrogradely labeled ganglion cells (cf. Partida et al, 2004). Tissues incubated in secondary antibodies without any primary antisera displayed no fluorescence at the confocal imaging and display settings used to generate any of the figures.…”

Section: Antibodiesmentioning

confidence: 99%

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HCN4-like immunoreactivity in rat retinal ganglion cells

Partida

Lee

et al. 2008

Vis Neurosci

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Antisera directed against hyperpolarization-activated, cyclic nucleotide-sensitive ("HCN") channels bind to somata in the ganglion cell layer of rat and rabbit retinas, and mRNA for different HCN channel isoforms has been detected in the ganglion cell layer of mouse retina. However, previous studies neither provided evidence that any of the somata are ganglion cells (as opposed to displaced amacrine cells) nor quantified these cells. We therefore tested whether isoform-specific anti-HCN channel antisera bind to ganglion cells labeled by retrograde transport of fluorophorecoupled dextran. In flat-mounted adult rat retinas, the number of dextran-backfilled ganglion cells agreed with cell densities reported in previous studies, and anti-HCN4 antisera bound to the somata of approximately 40% of these cells. The diameter of these somata ranged from 7 to 30 μm. Consistent with localization to cell membranes, the immunoreactivity formed a thin line that circumscribed individual somata. Optic fiber layer axon fascicles, and the proximal dendrites of some ganglion cells, also displayed binding of anti-HCN4 antisera. These results suggest that the response of some mammalian retinal ganglion cells to hyperpolarization may be modulated by changes in intracellular cAMP levels, and could thus be more complex than expected from previous voltage and current recordings.

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P48 is a predictive marker for outcome of postoperative interferon‐α treatment in patients with hepatitis B virus infection‐related hepatocellular carcinoma

Qian

Zhang

et al. 2006

Cancer

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BACKGROUND.Postoperative interferon‐α (IFN‐α) therapy improved survival in patients with hepatitis B virus (HBV)‐related hepatocellular carcinoma (HCC). The identification of predictive markers of outcome will help to select patients who are most likely to benefit from treatment.METHODS.An immunohistochemical study of P48 was performed on specimens that were collected from patients in a randomized trial who received postoperative IFN‐α therapy (Group 1; n = 80 patients) and who did not receive postoperative IFN‐α therapy (Group 2; n = 75 patients). Positive P48 expression was graded as ≥20% positive cells in 1 sample.RESULTS.Eighty‐one patients were positive for P48, and 74 patients were negative for P48. The clinicopathologic data were comparable between patients with P48‐negative and P48‐positive staining. Disease‐free survival (DFS) and overall survival (OS) in P48‐positive patients were better than that in P48‐negative patients in Group 1 (DFS, P = .036; OS, P = .014), however, DFS and OS did not differ between patients with positive and negative P48 in Group 2. OS in P48‐positive patients from Group 1 was better than that in patients with P48‐positive patients from Group 2 (OS, P = .001) but did not differ when P48 was negative. In Group 1, the risk factors for DFS were cirrhosis and P48 staining, and the risk factors for OS were tumor differentiation and P48 staining. Receiver operating curve analysis indicated that, in the first 2 years of DFS, combined cirrhosis and P48 had good predictive accuracy; and, in the first 4 years of OS, combined tumor differentiation and P48 had good predictive accuracy.CONCLUSIONS.P48 was useful as a predictive marker of outcome after postoperative IFN‐α treatment in patients with HBV‐related HCC. Cancer 2006. © 2006 American Cancer Society.

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DARPP‐32‐like immunoreactivity in AII amacrine cells of rat retina

Cited by 17 publications

References 85 publications

Electrical synapses between AII amacrine cells in the retina: Function and modulation

Electrical synapses between AII amacrine cells in the retina: Function and modulation

HCN4-like immunoreactivity in rat retinal ganglion cells

P48 is a predictive marker for outcome of postoperative interferon‐α treatment in patients with hepatitis B virus infection‐related hepatocellular carcinoma

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