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Li L. Sensory Integration: Cross-Modal Communication Between the Olfactory and Visual Systems in Zebrafish. Chem Senses 2019; 44:351-356. [PMID: 31066902 DOI: 10.1093/chemse/bjz022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cross-modal sensory communication is an innate biological process that refers to the combination and/or interpretation of different types of sensory input in the brain. Often, this process conjugates with neural modulation, by which the neural signals that convey sensory information are adjusted, such as intensity, frequency, complexity, and/or novelty. Although the anatomic pathways involved in cross-modal sensory integration have been previously described, the course of development and the physiological roles of multisensory signaling integration in brain functions remain to be elucidated. In this article, I review some of the recent findings in sensory integration from research using the zebrafish models. In zebrafish, cross-modal sensory integration occurs between the olfactory and visual systems. It is mediated by the olfacto-retinal centrifugal (ORC) pathway, which originates from the terminalis nerve (TN) in the olfactory bulb and terminates in the neural retina. In the retina, the TNs synapse with the inner nuclear layer dopaminergic interplexiform cells (DA-IPCs). Through the ORC pathway, stimulation of the olfactory neurons alters the cellular activity of TNs and DA-IPCs, which in turn modulates retinal neural function and increases behavioral visual sensitivity.
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Affiliation(s)
- Lei Li
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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Cui P, Li XY, Zhao Y, Li Q, Gao F, Li LZ, Yin N, Sun XH, Wang Z. Activation of dopamine D1 receptors enhances the temporal summation and excitability of rat retinal ganglion cells. Neuroscience 2017; 355:71-83. [DOI: 10.1016/j.neuroscience.2017.04.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 04/24/2017] [Accepted: 04/30/2017] [Indexed: 01/11/2023]
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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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Li Q, Wu N, Cui P, Gao F, Qian WJ, Miao Y, Sun XH, Wang Z. Suppression of outward K(+) currents by activating dopamine D1 receptors in rat retinal ganglion cells through PKA and CaMKII signaling pathways. Brain Res 2016; 1635:95-104. [PMID: 26826585 DOI: 10.1016/j.brainres.2016.01.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 01/17/2016] [Accepted: 01/21/2016] [Indexed: 01/11/2023]
Abstract
Dopamine plays an important role in regulating neuronal functions in the central nervous system by activating the specific G-protein coupled receptors. Both D1 and D2 dopamine receptors are extensively distributed in the retinal neurons. In the present study, we investigated the effects of D1 receptor signaling on outward K(+) currents in acutely isolated rat retinal ganglion cells (RGCs) by patch-clamp techniques. Extracellular application of SKF81297 (10 μM), a specific D1 receptor agonist, significantly and reversibly suppressed outward K(+) currents of the cells, which was reversed by SCH23390 (10 μM), a selective D1 receptor antagonist. We further showed that SKF81297 mainly suppressed the glybenclamide (Gb)- and 4-aminopyridine (4-AP)-sensitive K(+) current components, but did not show effect on the tetraethylammonium (TEA)-sensitive one. Both protein kinase A (PKA) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling pathways were likely involved in the SKF81297-induced suppression of the K(+) currents since either Rp-cAMP (10 μM), a cAMP/PKA signaling inhibitor, or KN-93 (10 μM), a specific CaMKII inhibitor, eliminated the SKF81297 effect. In contrast, neither protein kinase C (PKC) nor mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway seemed likely to be involved because both the PKC inhibitor bisindolylmaleimide IV (Bis IV) (10 μM) and the MAPK/ERK1/2 inhibitor U0126 (10 μM) did not block the SKF81297-induced suppression of the K(+) currents. These results suggest that activation of D1 receptors suppresses the Gb- and 4-AP-sensitive K(+) current components in rat RGCs through the intracellular PKA and CaMKII signaling pathways, thus modulating the RGC excitability.
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Affiliation(s)
- Qian Li
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Institute of Neurobiology, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Na Wu
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Peng Cui
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Institute of Neurobiology, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Feng Gao
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Wen-Jing Qian
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Institute of Neurobiology, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Yanying Miao
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Institute of Neurobiology, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Xing-Huai Sun
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
| | - Zhongfeng Wang
- Institutes of Brain Science, Fudan University, Shanghai 200032, China; Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai 200031, China; Institute of Neurobiology, Fudan University, Shanghai 200032, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
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Connaughton VP, Wetzell B, Arneson LS, DeLucia V, L. Riley A. Elevated dopamine concentration in light-adapted zebrafish retinas is correlated with increased dopamine synthesis and metabolism. J Neurochem 2015. [DOI: 10.1111/jnc.13264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Bradley Wetzell
- Department of Psychology; American University; Washington District of Columbia USA
| | - Lynne S. Arneson
- Department of Biology; American University; Washington District of Columbia USA
| | - Vittoria DeLucia
- Department of Biology; American University; Washington District of Columbia USA
| | - Anthony L. Riley
- Department of Psychology; American University; Washington District of Columbia USA
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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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Esposti F, Johnston J, Rosa JM, Leung KM, Lagnado L. Olfactory stimulation selectively modulates the OFF pathway in the retina of zebrafish. Neuron 2013; 79:97-110. [PMID: 23849198 PMCID: PMC3710973 DOI: 10.1016/j.neuron.2013.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2013] [Indexed: 01/11/2023]
Abstract
Cross-modal regulation of visual performance by olfactory stimuli begins in the retina, where dopaminergic interneurons receive projections from the olfactory bulb. However, we do not understand how olfactory stimuli alter the processing of visual signals within the retina. We investigated this question by in vivo imaging activity in transgenic zebrafish expressing SyGCaMP2 in bipolar cell terminals and GCaMP3.5 in ganglion cells. The food-related amino acid methionine reduced the gain and increased sensitivity of responses to luminance and contrast transmitted through OFF bipolar cells but not ON. The effects of olfactory stimulus were blocked by inhibiting dopamine uptake and release. Activation of dopamine receptors increased the gain of synaptic transmission in vivo and potentiated synaptic calcium currents in isolated bipolar cells. These results indicate that olfactory stimuli alter the sensitivity of the retina through the dopaminergic regulation of presynaptic calcium channels that control the gain of synaptic transmission through OFF bipolar cells. Olfactory stimuli regulate transmission of signals through retinal bipolar cells Modulation of synaptic gain and sensitivity occur in OFF bipolar cells but not ON An inhibitor of dopamine uptake blocks odor-induced changes in synaptic gain Dopamine potentiates presynaptic calcium channels in isolated bipolar cells
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Affiliation(s)
- Federico Esposti
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
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Schweitzer J, Lohr H, Filippi A, Driever W. Dopaminergic and noradrenergic circuit development in zebrafish. Dev Neurobiol 2012; 72:256-68. [PMID: 21567980 DOI: 10.1002/dneu.20911] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Dopaminergic and noradrenergic neurons constitute some of the major far projecting systems in the vertebrate brain and spinal cord that modulate the activity of circuits controlling a broad range of behaviors. Degeneration or dysfunction of dopaminergic neurons has also been linked to a number of neurological and psychiatric disorders, including Parkinson's disease.Zebrafish (Danio rerio) have emerged over the past two decades into a major genetic vertebrate model system,and thus contributed to a better understanding of developmental mechanisms controlling dopaminergic neuron specification and axonogenesis. In this review, we want to focus on conserved and dynamic aspects of the different catecholaminergic systems, which may help to evaluate the zebrafish as a model for dopaminergic and noradrenergic cellular specification and circuit function as well as biomedical aspects of catecholamine systems.
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Abstract
AbstractZebrafish are an existing model for genetic and developmental studies due to their rapid external development and transparent embryos, which allow easy manipulation and observation of early developmental stages. The application of the zebrafish model to vision research has allowed for examination of retinal development and the characteristics of different retinal cell types, including bipolar cells. In particular, bipolar cell development, including differentiation, maturation, and gene expression, has been documented, as has physiological properties, such as voltage- and ligand-gated currents, and neurotransmitter receptor and ion channel expression. Mutant strains and transgenic lines have been used to document how bipolar cell connections and/or development may be altered, and toxicological studies examining how environmental factors may impact bipolar cell activity have been performed. The purpose of this paper was to review the existing literature on zebrafish bipolar cells, to provide a comprehensive overview of current information pertaining to this retinal cell type.
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Huang L, Li L. Characterization of voltage-activated ionic currents in the GnRH-containing terminalis nerve in transgenic zebrafish. Brain Res 2010; 1367:43-9. [PMID: 20951681 DOI: 10.1016/j.brainres.2010.10.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 12/29/2022]
Abstract
The terminalis nerve (TN) is in a class of cranial nerves that plays important roles in animal development, physiology and behavior. Here, we report a study on the characterization of voltage-activated ionic currents in GnRH-containing TN cells in zebrafish. The experiments were performed using acutely dissociated TN cells from the transgenic zebrafish Tg (GnRH-3::GFP). In the transgenic zebrafish, the TN cells express GFP under the transcriptional control of the zebrafish GnRH-3 promoter. In all of the GnRH-containing TN cells examined, we recorded both low-voltage-activated (LVA) and high-voltage-activated (HVA) calcium current (I(Ca)). The characteristics of the I(Ca) were similar to those described in other zebrafish cell types. However, the distribution patterns of the currents in the GnRH-containing TN cells were different in comparison to the distribution of the currents in other cell types. In addition, we characterized TTX-sensitive sodium current (I(Na)) and 4AP-sensitive and TEA-resistant potassium current (I(K)). The characteristics of voltage-activated I(Na) and I(K) in the GnRH-containing TN cells were similar to those described in other zebrafish cell types. Together, the data from this study revealed the electrophysiological properties of the GnRH-containing TN cells, thereby providing insight on the regulatory mechanisms of TN-signaling in animal physiology.
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Affiliation(s)
- Luoxiu Huang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
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Guo S. Using zebrafish to assess the impact of drugs on neural development and function. Expert Opin Drug Discov 2009; 4:715-726. [PMID: 19774094 DOI: 10.1517/17460440902988464] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND: Zebrafish is becoming an increasingly attractive model organism for understanding biology and developing therapeutics, because as a vertebrate, it shares considerable similarity with mammals in both genetic compositions and tissue/organ structures, and yet remains accessible to high throughput phenotype-based genetic and small molecule compound screening. OBJECTIVE/METHOD: The focus of this review is on the nervous system, which is arguably the most complex organ and known to be afflicted by more than six hundred disorders in humans. I discuss the past, present, and future of using zebrafish to assess the impact of small molecule drugs on neural development and function, in light of understanding and treating neurodevelopmental disorders such as autism, neurodegenerative disorders including Alzheimer's, Parkinson's, and Hungtington's disease, and neural system dysfunctions such as anxiety/depression and addiction. CONCLUSION: These studies hold promise to reveal fundamental mechanisms governing nervous system development and function, and to facilitate small molecule drug discovery for the many types of neurological disorders.
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Affiliation(s)
- Su Guo
- Department of Biopharmaceutical Sciences, Programs in Biological Sciences and Human Genetics, Institute for Regenerative Medicine, University of California San Francisco, CA 94143-2811
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Yu YC, Satoh H, Wu SM, Marshak DW. Histamine enhances voltage-gated potassium currents of ON bipolar cells in macaque retina. Invest Ophthalmol Vis Sci 2008; 50:959-65. [PMID: 18836167 DOI: 10.1167/iovs.08-2746] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The goal was to understand the functions of retinopetal axons containing histamine. In prior work, type 3 histamine receptors (HR3) have been localized to the tips of ON bipolar cell dendrites in macaque retinas. Voltage-gated potassium channels have also been localized to bipolar cell dendrites, and the hypothesis tested in the present study was that these are modulated by histamine. METHODS Whole-cell recordings of potassium currents were made from bipolar cells in slice preparations of macaque retina. In voltage-clamp mode, the cells were held at -60 mV and stepped to values from -60 to 80 mV. Recordings of the membrane potential were also made in current-clamp mode. Histamine, the HR3 agonist (R) alpha-methylhistamine (RAMH), tetraethyl ammonium (TEA), and 4-aminopyridine (4-AP) were applied in the superfusate. RESULTS Histamine produced a dose-dependent increase in potassium currents in a subset of bipolar cells. At 5 microM, histamine increased the currents by 15% or more in the ON bipolar cells but not in the OFF bipolar cells. RAMH at 5 microM increased the amplitude of the potassium currents in the ON bipolar cells. In 10 mM TEA, potassium currents were reduced in all the bipolar cells, and there was no effect of histamine. Histamine hyperpolarized the resting membrane potential of the ON bipolar cells by 5 mV. CONCLUSIONS By enhancing potassium currents in the ON bipolar cells, histamine is expected to reduce the amplitude of the light responses and limit their duration. The hyperpolarization of the resting membrane potential would also reduce neurotransmitter release at their output synapses.
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Affiliation(s)
- Yong-Chun Yu
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, Texas 77225, USA
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13
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Recent papers on zebrafish and other aquarium fish models. Zebrafish 2008; 2:215-24. [PMID: 18248196 DOI: 10.1089/zeb.2005.2.215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Weber DN, Connaughton VP, Dellinger JA, Klemer D, Udvadia A, Carvan MJ. Selenomethionine reduces visual deficits due to developmental methylmercury exposures. Physiol Behav 2007; 93:250-60. [PMID: 17905328 PMCID: PMC2265788 DOI: 10.1016/j.physbeh.2007.08.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 07/09/2007] [Accepted: 08/29/2007] [Indexed: 11/26/2022]
Abstract
Developmental exposures to methylmercury (MeHg) have life-long behavioral effects. Many micronutrients, including selenium, are involved in cellular defenses against oxidative stress and may reduce the severity of MeHg-induced deficits. Zebrafish embryos (<4 h post fertilization, hpf) were exposed to combinations of 0.0-0.30 microM MeHg and/or selenomethionine (SeMet) until 24 hpf then placed in clean medium. Fish were tested as adults under low light conditions ( approximately 60 microW/m(2)) for visual responses to a rotating black bar. Dose-dependent responses to MeHg exposure were evident (ANOVA, P<0.001) as evidenced by reduced responsiveness, whereas SeMet did not induce deficits except at 0.3 microM. Ratios of SeMet:MeHg of 1:1 or 1:3 resulted in responses that were indistinguishable from controls (ANOVA, P<0.001). No gross histopathologies were observed (H&E stain) in the retina or optic tectum at any MeHg concentration. Whole-cell, voltage-gated, depolarization-elicited outward K(+) currents of bipolar cells in intact retina of slices adult zebrafish were recorded and outward K(+) current amplitude was larger in bipolar cells of MeHg-treated fish. This was due to the intense response of cells expressing the delayed rectifying I(K) current; cells expressing the transient I(A) current displayed a slight trend for smaller amplitude among MeHg-treated fish. Developmental co-exposure to SeMet reduced but did not eliminate the increase in the MeHg-induced I(K) response, however, I(A) responses increased significantly over MeHg-treated fish to match control levels. Electrophysiological deficits parallel behavioral patterns in MeHg-treated fish, i.e., initial reactions to the rotating bar were followed by periods of inactivity and then a resumption of responses.
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Affiliation(s)
- Daniel N Weber
- Marine and Freshwater Biomedical Sciences Center, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, United States.
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Huang L, Li L. Differential expression of voltage-activated calcium currents in zebrafish retinal ganglion cells. J Neurosci Res 2006; 84:497-504. [PMID: 16721759 DOI: 10.1002/jnr.20951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report a study on the characterization of voltage-activated calcium currents (I(Ca)) in retinal ganglion cells (RGCs) and the topographic distribution of RGCs that express different types of I(Ca) in zebrafish retinas. In acutely isolated zebrafish RGCs, both high-voltage-activated (HVA; peak activation potential +7.4 +/- 1.1 mV) and low-voltage-activated (LVA; peak activation potential -33.0 +/- 1.2 mV) I(Ca) were recorded. HVA I(Ca) were recorded in all of the tested RGCs, whereas LVA I(Ca) were recorded in approximately one-third of the tested cells. In RGCs that expressed both HVA and LVA I(Ca), the two currents were readily separated by depolarizing the cell membrane to different voltages from different holding potentials. Among RGCs that expressed LVA I(Ca), some cells expressed large LVA I(Ca) (up to 130 pA), whereas others expressed small LVA I(Ca) (approximately 20 pA). RGCs that expressed large and small LVA I(Ca) were designated as class I and class II cells, respectively, and RGCs that expressed only HVA I(Ca) were designated as class III cells. The topographic distribution of cell classes was similar in various areas of the retina. In the nasal-ventral retina, for example, class III cells outnumbered class I and class II cells by 10.8- and 2.6-fold, respectively. In the temporal and dorsal retinas, the density of class III cells slightly decreased, whereas the density of class I and class II cells increased. The differential expression of I(Ca) in RGCs may correlate with the development and function of the retina.
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Affiliation(s)
- Luoxiu Huang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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Huang L, Maaswinkel H, Li L. Olfactoretinal centrifugal input modulates zebrafish retinal ganglion cell activity: a possible role for dopamine-mediated Ca2+ signalling pathways. J Physiol 2005; 569:939-48. [PMID: 16239263 PMCID: PMC1464265 DOI: 10.1113/jphysiol.2005.099531] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The vertebrate retina receives centrifugal input from the brain. In zebrafish, the major centrifugal input originates in the terminal nerve (TN). TN cell bodies are located in the olfactory bulb and ventral telencephalon. The TN projects axons to the retina where they branch in the inner plexiform layer (IPL) and synapse onto several inner retinal cell types, including dopaminergic interplexiform cells (DA-IPCs). This olfactoretinal centrifugal input plays a role in modulating retinal ganglion cell (RGC) activity, probably via dopamine-mediated Ca2+ signalling pathways. Normally, dopamine inhibits RGC firing by decreasing the inward Ca2+ current. Olfactory stimulation with amino acids decreases dopamine release in the retina, thereby reducing dopaminergic inhibition of RGCs. This model of olfacto-visual integration was directly tested by recording single-unit RGC activity in response to olfactory stimulation in the presence or absence of dopamine receptor blockers. Stimulation of the olfactory neurones increased RGC activity. However, this effect diminished when the dopamine D1 receptors were pharmacologically blocked. In isolated RGCs, the application of dopamine or a dopamine D1 receptor agonist decreased voltage-activated Ca2+ current and lowered Ca2+ influx. Together, the data suggest that olfactory input has a modulatory effect on RGC firing, and that this effect is mediated by dopamine D1 receptor-coupled Ca2+ signalling pathways.
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Affiliation(s)
- Luoxiu Huang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
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