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Chrispell JD, Xiong Y, Weiss ER. Grk7 but not Grk1 undergoes cAMP-dependent phosphorylation in zebrafish cone photoreceptors and mediates cone photoresponse recovery to elevated cAMP. J Biol Chem 2022; 298:102636. [PMID: 36273582 PMCID: PMC9692042 DOI: 10.1016/j.jbc.2022.102636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
In the vertebrate retina, phosphorylation of photoactivated visual pigments in rods and cones by G protein-coupled receptor kinases (GRKs) is essential for sustained visual function. Previous in vitro analysis demonstrated that GRK1 and GRK7 are phosphorylated by PKA, resulting in a reduced capacity to phosphorylate rhodopsin. In vivo observations revealed that GRK phosphorylation occurs in the dark and is cAMP dependent. In many vertebrates, including humans and zebrafish, GRK1 is expressed in both rods and cones while GRK7 is expressed only in cones. However, mice express only GRK1 in both rods and cones and lack GRK7. We recently generated a mutation in Grk1 that deletes the phosphorylation site, Ser21. This mutant demonstrated delayed dark adaptation in mouse rods but not in cones in vivo, suggesting GRK1 may serve a different role depending upon the photoreceptor cell type in which it is expressed. Here, zebrafish were selected to evaluate the role of cAMP-dependent GRK phosphorylation in cone photoreceptor recovery. Electroretinogram analyses of larvae treated with forskolin show that elevated intracellular cAMP significantly decreases recovery of the cone photoresponse, which is mediated by Grk7a rather than Grk1b. Using a cone-specific dominant negative PKA transgene, we show for the first time that PKA is required for Grk7a phosphorylation in vivo. Lastly, immunoblot analyses of rod grk1a-/- and cone grk1b-/- zebrafish and Nrl-/- mouse show that cone-expressed Grk1 does not undergo cAMP-dependent phosphorylation in vivo. These results provide a better understanding of the function of Grk phosphorylation relative to cone adaptation and recovery.
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Chen XJ, Li ML, Wang YH, Mou H, Wu Z, Bao S, Xu ZH, Zhang H, Wang XY, Zhang CJ, Xue X, Jin ZB. Abundant Neural circRNA Cdr1as Is Not Indispensable for Retina Maintenance. Front Cell Dev Biol 2020; 8:565543. [PMID: 33240875 PMCID: PMC7677238 DOI: 10.3389/fcell.2020.565543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/16/2020] [Indexed: 12/22/2022] Open
Abstract
Cdr1as is the abundant circular RNA (circRNA) in human and vertebrate retinas. However, the role of Cdr1as in the retina remains unknown. In this study, we aimed to generate a Cdr1as knockout (KO) mouse model and investigate the retinal consequences of Cdr1as loss of function. Through in situ hybridization (ISH), we demonstrated that Cdr1as is mainly expressed in the inner retina. Using CRISPR/Cas9 targeting Cdr1as, we successfully generated KO mice. We carried out ocular examinations in the KO mice until postnatal day 500. Compared with the age-matched wild-type (WT) siblings, the KO mice displayed increased b-wave amplitude of photopic electrophysiological response and reduced vision contrast sensitivity. Through small RNA profiling of the retinas, we determined that miR-7 was downregulated, while its target genes were upregulated. Taken together, our results demonstrated for the first time that Cdr1as ablation led to a mild retinal consequence in mice, indicating that Cdr1as abundance is not indispensable for retinal development and maintenance.
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Affiliation(s)
- Xue-Jiao Chen
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Meng-Lan Li
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Ya-Han Wang
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Hao Mou
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Zhen Wu
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Siqi Bao
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Ze-Hua Xu
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Hang Zhang
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Xiao-Yun Wang
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Chang-Jun Zhang
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Xiangyang Xue
- School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Zi-Bing Jin
- School of Ophthalmology and Optometry and Eye Hospital, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China.,School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China.,Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
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Lee M, Leskova W, Eshaq RS, Harris NR. Acute changes in the retina and central retinal artery with methamphetamine. Exp Eye Res 2020; 193:107964. [PMID: 32044305 DOI: 10.1016/j.exer.2020.107964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/05/2020] [Accepted: 02/05/2020] [Indexed: 12/12/2022]
Abstract
Methamphetamine (METH), an addictive stimulant of neurotransmitters, is associated with cardiovascular and neurological diseases. METH-induced ophthalmic complications are also present but have been insufficiently investigated. The purpose of this study is to investigate the retinal effects of METH. C57BL/6 mice were administrated progressively increasing doses of METH (0-6 mg/kg) by repetitive intraperitoneal injections for 5 days (4 times per day). Retinal degeneration was examined by morphological changes and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Norepinephrine levels were measured by ELISA, protein expression levels were determined by immunoblot and immunostaining, and gelatinase activity was examined by zymography. The thickness of the retina and the number of nuclei in the inner and outer nuclear layers were decreased by METH. Retinal cell death and astrocyte activation by METH treatment were confirmed by TUNEL assay and glial fibrillary acidic protein expression, respectively. Increased tumor necrosis factor-α protein in the retina and elevated norepinephrine levels in plasma were found in METH-treated mice. Platelet endothelial cell adhesion molecule-1 (PECAM-1) protein expression level was decreased in the retina and central retinal artery (CRA) by METH treatment, along with the endothelial proteoglycans glypican-1 and syndecan-1. Moreover, a regulator of the extracellular matrix, matrix metalloproteinase-14 (MMP-14) in the retina, and MMP-2 and MMP-9 in plasma, were increased by METH treatment. In conclusion, METH administration is involved in retinal degeneration with a vascular loss of PECAM-1 and the glycocalyx in the CRA and retina, and an increase of MMPs.
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Affiliation(s)
- Minsup Lee
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, 71103, USA
| | - Wendy Leskova
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, 71103, USA
| | - Randa S Eshaq
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, 71103, USA
| | - Norman R Harris
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, 71103, USA.
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Chrispell JD, Dong E, Osawa S, Liu J, Cameron DJ, Weiss ER. Grk1b and Grk7a Both Contribute to the Recovery of the Isolated Cone Photoresponse in Larval Zebrafish. Invest Ophthalmol Vis Sci 2018; 59:5116-5124. [PMID: 30372740 PMCID: PMC6203174 DOI: 10.1167/iovs.18-24455] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
Purpose To define the functional roles of Grk1 and Grk7 in zebrafish cones in vivo. Methods Genome editing was used to generate grk7a and grk1b knockout zebrafish. Electroretinogram (ERG) analyses of the isolated cone mass receptor potential and the b-wave were performed in dark-adapted zebrafish using a paired flash paradigm to determine recovery of cone photoreceptors and the inner retina after an initial flash. In addition, psychophysical visual response was measured using the optokinetic response (OKR). Results ERG analysis demonstrated that deletion of either Grk1b or Grk7a in zebrafish larvae resulted in modestly lower rates of recovery of the isolated cone mass receptor potential from an initial flash compared to wildtype larvae. On the other hand, grk1b-/- and grk7a-/- larvae exhibited a b-wave recovery that was similar to wildtype larvae. We evaluated the OKR and found that deletion of either Grk1b or Grk7a leads to a small decrease in temporal contrast sensitivity and alterations in visual acuity. Conclusions For the first time, we demonstrate that Grk1b and Grk7a both contribute to visual function in larval zebrafish cones. Since the difference between wildtype and each knockout fish is modest, it appears that either GRK is sufficient for adequate cone visual function.
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Affiliation(s)
- Jared D. Chrispell
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Enheng Dong
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Shoji Osawa
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Jiandong Liu
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - D. Joshua Cameron
- College of Optometry, Western University of Health Sciences, Pomona, California, United States
| | - Ellen R. Weiss
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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Huang F, Zhang L, Wang Q, Yang Y, Li Q, Wu Y, Chen J, Qu J, Zhou X. Dopamine D1 Receptors Contribute Critically to the Apomorphine-Induced Inhibition of Form-Deprivation Myopia in Mice. ACTA ACUST UNITED AC 2018; 59:2623-2634. [PMID: 29847669 DOI: 10.1167/iovs.17-22578] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Furong Huang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Lishuai Zhang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Qiongsi Wang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Yanan Yang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Qihang Li
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Yi Wu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jiangfan Chen
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jia Qu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Xiangtian Zhou
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
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Popova E, Kupenova P. Dopamine D2 receptor blockade differentially affects the light-adapted turtle and frog electroretinogram. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Popova E, Kostov M, Kupenova P. Effects of dopamine D 1 receptor blockade on the ERG b- and d-waves during blockade of ionotropic GABA receptors. EYE AND VISION 2016; 3:32. [PMID: 27981058 PMCID: PMC5142325 DOI: 10.1186/s40662-016-0064-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
Abstract
Background Some data indicate that the dopaminergic and GABAergic systems interact in the vertebrate retina, but the type of interactions is not well understood. Methods In this study we investigated the effect of dopamine D1 receptor blockade by 75 μM SCH 23390 on the electroretinographic ON (b-wave) and OFF (d-wave) responses in intact frog eyecup preparations and in eyecups where the ionotropic GABA receptors were blocked by 50 μM picrotoxin. Student’s t-test, One-way repeated measures ANOVA with Bonferroni post-hoc test and Two-way ANOVA were used for statistical evaluation of the data. Results We found that SCH 23390 alone significantly enhanced the amplitude of the b- and d-waves without altering their latency. The effect developed rapidly and was fully expressed within 8-11 min after the blocker application. Picrotoxin alone also markedly enhanced the amplitude of the ERG ON and OFF responses and increased their latency significantly. The effect was fully expressed within 25-27 min after picrotoxin application and remained very stable in the next 20 min. The effects of SCH 23390 and picrotoxin are similar to that reported in our previous studies. When SCH 23390 was applied on the background of the fully developed picrotoxin effect, it diminished the amplitude of the b- and d-waves in comparison to the corresponding values obtained during application of picrotoxin alone. Conclusion Our results demonstrate that the enhancing effect of D1 receptor blockade on the amplitude of the ERG b- and d-waves is not evident during the ionotropic GABA receptor blockade, indicating an interaction between these neurotransmitter systems in the frog retina. We propose that the inhibitory effect of endogenous dopamine mediated by D1 receptors on the ERG ON and OFF responses in the frog retina may be due to the dopamine-evoked GABA release. Electronic supplementary material The online version of this article (doi:10.1186/s40662-016-0064-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elka Popova
- Department of Physiology, Medical University of Sofia, Sofia, Bulgaria
| | - Momchil Kostov
- Department of Physiology, Medical University of Sofia, Sofia, Bulgaria
| | - Petia Kupenova
- Department of Physiology, Medical University of Sofia, Sofia, Bulgaria
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Deming JD, Pak JS, Brown BM, Kim MK, Aung MH, Eom YS, Shin JA, Lee EJ, Pardue MT, Craft CM. Visual Cone Arrestin 4 Contributes to Visual Function and Cone Health. Invest Ophthalmol Vis Sci 2015; 56:5407-16. [PMID: 26284544 DOI: 10.1167/iovs.15-16647] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Visual arrestins (ARR) play a critical role in shutoff of rod and cone phototransduction. When electrophysiological responses are measured for a single mouse cone photoreceptor, ARR1 expression can substitute for ARR4 in cone pigment desensitization; however, each arrestin may also contribute its own, unique role to modulate other cellular functions. METHODS A combination of ERG, optokinetic tracking, immunohistochemistry, and immunoblot analysis was used to investigate the retinal phenotypes of Arr4 null mice (Arr4-/-) compared with age-matched control, wild-type mice. RESULTS When 2-month-old Arr4-/- mice were compared with wild-type mice, they had diminished visual acuity and contrast sensitivity, yet enhanced ERG flicker response and higher photopic ERG b-wave amplitudes. In contrast, in older Arr4-/- mice, all ERG amplitudes were significantly reduced in magnitude compared with age-matched controls. Furthermore, in older Arr4-/- mice, the total cone numbers decreased and cone opsin protein immunoreactive expression levels were significantly reduced, while overall photoreceptor outer nuclear layer thickness was unchanged. CONCLUSIONS Our study demonstrates that Arr4-/- mice display distinct phenotypic differences when compared to controls, suggesting that ARR4 modulates essential functions in high acuity vision and downstream cellular signaling pathways that are not fulfilled or substituted by the coexpression of ARR1, despite its high expression levels in all mouse cones. Without normal ARR4 expression levels, cones slowly degenerate with increasing age, making this a new model to study age-related cone dystrophy.
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Affiliation(s)
- Janise D Deming
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Joseph S Pak
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Bruce M Brown
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Moon K Kim
- Rehabilitation Research & Development Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia, United States
| | - Moe H Aung
- Neuroscience/Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Yun Sung Eom
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 4Dornsife College of Letters, Arts and Sciences, Univers
| | - Jung-A Shin
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 5Department of Anatomy, School of Medicine, Ewha Womans
| | - Eun-Jin Lee
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 6Department of Biomedical Engineering, University of Sou
| | - Machelle T Pardue
- Rehabilitation Research & Development Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia, United States 3Neuroscience/Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Cheryl Mae Craft
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States 7Department of Cell & Neurobiology, Keck School of Medic
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Chrispell JD, Rebrik TI, Weiss ER. Electroretinogram analysis of the visual response in zebrafish larvae. J Vis Exp 2015:52662. [PMID: 25867216 PMCID: PMC4401321 DOI: 10.3791/52662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The electroretinogram (ERG) is a noninvasive electrophysiological method for determining retinal function. Through the placement of an electrode on the surface of the cornea, electrical activity generated in response to light can be measured and used to assess the activity of retinal cells in vivo. This manuscript describes the use of the ERG to measure visual function in zebrafish. Zebrafish have long been utilized as a model for vertebrate development due to the ease of gene suppression by morpholino oligonucleotides and pharmacological manipulation. At 5-10 dpf, only cones are functional in the larval retina. Therefore, the zebrafish, unlike other animals, is a powerful model system for the study of cone visual function in vivo. This protocol uses standard anesthesia, micromanipulation and stereomicroscopy protocols that are common in laboratories that perform zebrafish research. The outlined methods make use of standard electrophysiology equipment and a low light camera to guide the placement of the recording microelectrode onto the larval cornea. Finally, we demonstrate how a commercially available ERG stimulator/recorder originally designed for use with mice can easily be adapted for use with zebrafish. ERG of larval zebrafish provides an excellent method of assaying cone visual function in animals that have been modified by morpholino oligonucleotide injection as well as newer genome engineering techniques such as Zinc Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs), and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9, all of which have greatly increased the efficiency and efficacy of gene targeting in zebrafish. In addition, we take advantage of the ability of pharmacological agents to penetrate zebrafish larvae to evaluate the molecular components that contribute to the photoresponse. This protocol outlines a setup that can be modified and used by researchers with various experimental goals.
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Affiliation(s)
- Jared D Chrispell
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill
| | | | - Ellen R Weiss
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill;
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Oh S. Bisphenol A and 4-tert-Octylphenol Inhibit Cx46 Hemichannel Currents. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 19:73-9. [PMID: 25606000 PMCID: PMC4297765 DOI: 10.4196/kjpp.2015.19.1.73] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 11/21/2022]
Abstract
Connexins (Cx) are membrane proteins and monomers for forming gap junction (GJ) channels. Cx46 and Cx50 are also known to function as conductive hemichannels. As part of an ongoing effort to find GJ-specific blocker(s), endocrine disruptors were used to examine their effect on Cx46 hemichannels expressed in Xenopus oocytes. Voltage-dependent gating of Cx46 hemichannels was characterized by slowly activating outward currents and relatively fast inward tail currents. Bisphenol A (BPA, 10 nM) reduced outward currents of Cx46 hemichannels up to ~18% of control, and its effect was reversible (n=5). 4-tert-Octylphenol (OP, 1 µM) reversibly reduced outward hemichannel currents up to ~28% (n=4). However, overall shapes of Cx46 hemichannel current traces (outward and inward currents) were not changed by these drugs. These results suggest that BPA and OP are likely to occupy the pore of Cx46 hemichannels and thus obstruct the ionic fluxes. This finding provides that BPA and OP are potential candidates for GJ channel blockers.
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Affiliation(s)
- Seunghoon Oh
- Department of Physiology, College of Medicine, Dankook University, Cheonan 330-714, Korea
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11
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Tian N, Xu HP, Wang P. Dopamine D2 receptors preferentially regulate the development of light responses of the inner retina. Eur J Neurosci 2014; 41:17-30. [PMID: 25393815 DOI: 10.1111/ejn.12783] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/25/2014] [Accepted: 10/13/2014] [Indexed: 01/14/2023]
Abstract
Retinal light responsiveness measured via electroretinography undergoes developmental modulation, and is thought to be critically regulated by both visual experience and dopamine. The primary goal of this study was to determine whether dopamine D2 receptors regulate the visual experience-dependent functional development of the retina. Accordingly, we recorded electroretinograms from wild-type mice and mice with a genetic deletion of the gene that encodes the D2 receptor raised under normal cyclic light conditions and constant darkness. Our results demonstrate that D2 receptor mutation preferentially increases the amplitude of the inner retinal light responses evoked by high-intensity light measured as oscillatory potentials in adult mice. During postnatal development, all three major components of electroretinograms, i.e. a-waves, b-waves, and oscillatory potentials, increase with age. Comparatively, D2 receptor mutation preferentially reduces the age-dependent increase in b-waves evoked by low-intensity light. Light deprivation from birth reduces b-wave amplitudes and completely abolishes the increased amplitude of oscillatory potentials of D2 receptor mutants. Taken together, these results demonstrate that D2 receptors play an important role in the activity-dependent functional development of the mouse retina.
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Affiliation(s)
- Ning Tian
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT, 84132, USA
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Palacios-Muñoz A, Escobar MJ, Vielma A, Araya J, Astudillo A, Valdivia G, García IE, Hurtado J, Schmachtenberg O, Martínez AD, Palacios AG. Role of connexin channels in the retinal light response of a diurnal rodent. Front Cell Neurosci 2014; 8:249. [PMID: 25202238 PMCID: PMC4142540 DOI: 10.3389/fncel.2014.00249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 08/05/2014] [Indexed: 01/02/2023] Open
Abstract
Several studies have shown that connexin channels play an important role in retinal neural coding in nocturnal rodents. However, the contribution of these channels to signal processing in the retina of diurnal rodents remains unclear. To gain insight into this problem, we studied connexin expression and the contribution of connexin channels to the retinal light response in the diurnal rodent Octodon degus (degu) compared to rat, using in vivo ERG recording under scotopic and photopic light adaptation. Analysis of the degu genome showed that the common retinal connexins present a high degree of homology to orthologs expressed in other mammals, and expression of Cx36 and Cx43 was confirmed in degu retina. Cx36 localized mainly to the outer and inner plexiform layers (IPLs), while Cx43 was expressed mostly in cells of the retinal pigment epithelium. Under scotopic conditions, the b-wave response amplitude was strongly reduced by 18-β-glycyrrhetinic acid (β-GA) (−45.1% in degu, compared to −52.2% in rat), suggesting that connexins are modulating this response. Remarkably, under photopic adaptation, β-GA increased the ERG b-wave amplitude in degu (+107.2%) while reducing it in rat (−62.3%). Moreover, β-GA diminished the spontaneous action potential firing rate in ganglion cells (GCs) and increased the response latency of ON and OFF GCs. Our results support the notion that connexins exert a fine-tuning control of the retinal light response and have an important role in retinal neural coding.
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Affiliation(s)
- Angelina Palacios-Muñoz
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Maria J Escobar
- Departamento de Electrónica, Universidad Técnico Federico Santa María Valparaíso, Chile
| | - Alex Vielma
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Joaquín Araya
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Aland Astudillo
- Departamento de Electrónica, Universidad Técnico Federico Santa María Valparaíso, Chile
| | - Gonzalo Valdivia
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Isaac E García
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - José Hurtado
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile ; Instituto de Sistemas Complejos de Valparaíso Valparaíso, Chile
| | - Oliver Schmachtenberg
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Agustín D Martínez
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Adrian G Palacios
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile ; Instituto de Sistemas Complejos de Valparaíso Valparaíso, Chile
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Popova E. Role of dopamine in distal retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:333-58. [PMID: 24728309 DOI: 10.1007/s00359-014-0906-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 01/11/2023]
Abstract
Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.
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Affiliation(s)
- E Popova
- Department of Physiology, Medical Faculty, Medical University, 1431, Sofia, Bulgaria,
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He Q, Xu HP, Wang P, Tian N. Dopamine D1 receptors regulate the light dependent development of retinal synaptic responses. PLoS One 2013; 8:e79625. [PMID: 24260267 PMCID: PMC3834122 DOI: 10.1371/journal.pone.0079625] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 10/02/2013] [Indexed: 12/30/2022] Open
Abstract
Retinal synaptic connections and function are developmentally regulated. Retinal synaptic activity plays critical roles in the development of retinal synaptic circuitry. Dopamine receptors have been thought to play important roles in the activity-dependent synaptic plasticity in central nervous system. The primary goal of this study is to determine whether dopamine D1 receptor regulates the activity-dependent development of retinal light responsiveness. Accordingly, we recorded electroretinogram from wild type mice and mice with genetic deletion of D1 dopamine receptor (D1-/- mice) raised under cyclic light conditions and constant darkness. Our results demonstrated that D1-/- mice have reduced amplitudes of all three major components of electroretinogram in adulthood. When the relative strength of the responses is considered, the D1-/- mice have selective reduction of the amplitudes of a-wave and oscillatory potentials evoked by low-intermediate intensities of lights. During postnatal development, D1-/- mice have increased amplitude of b-wave at the time of eye-opening but reduced developmental increase of the amplitude of b-wave after eye opening. Light deprivation from birth significantly reduced the amplitudes of b-wave and oscillatory potentials, increased the outer retinal light response gain and altered the light response kinetics of both a- and b-waves of wild type mice. In D1-/- mice, the effect of dark rearing on the amplitude of oscillatory potentials was diminished and dark rearing induced effects on the response gain of outer retina and the kinetics of a-wave were reversed. These results demonstrated roles of dopamine D1 receptor in the activity-dependent functional development of mouse retina.
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Affiliation(s)
- Quanhua He
- College of Pharmacy, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Hong-ping Xu
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Ping Wang
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ning Tian
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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Effects of dopamine receptor blockade on the intensity-response function of electroretinographic b- and d-waves in light-adapted eyes. J Neural Transm (Vienna) 2013; 121:233-44. [PMID: 24150276 DOI: 10.1007/s00702-013-1103-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 10/11/2013] [Indexed: 01/11/2023]
Abstract
The effects of dopamine receptor blockade by sulpiride (D2-class antagonist) and sulpiride plus SCH 23390 (D1-class antagonist) on the V - log I function of the electroretinographic (ERG) b- and d-waves were investigated in light-adapted frog eyes. Sulpiride significantly decreased the absolute sensitivity of the b- and d-waves. The amplitude of the both waves was diminished over the whole intensity range studied. A similar effect on the b-, but not d-wave amplitude was seen during the perfusion with sulpiride plus SCH 23390. The effect on the d-wave amplitude depended on stimulus intensity. The threshold of the d-wave was not significantly altered. The suprathreshold d-wave amplitude was enhanced at the lower stimulus intensities and remained unchanged at the higher ones. The results obtained indicate that the action of endogenous dopamine on the photopic ERG shows clear ON-OFF asymmetry. Participation of different classes of dopamine receptors is probably responsible for this difference.
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Popova E, Kupenova P. Effects of dopamine receptor blockade on the intensity-response function of ERG b- and d-waves in dark adapted eyes. Vision Res 2013; 88:22-9. [PMID: 23810982 DOI: 10.1016/j.visres.2013.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/26/2013] [Accepted: 06/15/2013] [Indexed: 01/11/2023]
Abstract
The effects of dopamine receptor blockade by sulpiride (D2-class antagonist) and sulpiride plus SCH 23390 (D1-class antagonist) on the V - log I function of the ERG b- and d-waves were investigated in dark adapted frog eyes. We observed that sulpiride enhanced the amplitude of the suprathreshold b- and d-waves in the lower intensity range, where the responses were mediated by rods, but diminished it in the higher intensity range, where the responses were mediated by cones. A similar effect on the b-, but not d-wave amplitude was seen during the perfusion with sulpiride plus SCH 23390. The d-wave amplitude was enhanced over the whole intensity range with the exception of the highest intensities during the combined D1 and D2 receptor blockade. The results obtained indicate that the endogenous dopamine has an overall inhibitory action on the suprathreshold rod-mediated ON and OFF responses, while its action on the cone-mediated responses shows clear ON-OFF asymmetry. It is excitatory upon the ON responses, but inhibitory upon the OFF responses except for those in the highest intensity range. Participation of different types of dopamine receptors (predominantly D2 for the ON versus D1 for the OFF response) is probably responsible for this difference.
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Affiliation(s)
- E Popova
- Department of Physiology, Medical Faculty, Medical University of Sofia, 1431 Sofia, Bulgaria.
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