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Kumar D, Khan B, Okcay Y, Sis ÇÖ, Abdallah A, Murray F, Sharma A, Uemura M, Taliyan R, Heinbockel T, Rahman S, Goyal R. Dynamic endocannabinoid-mediated neuromodulation of retinal circadian circuitry. Ageing Res Rev 2024; 99:102401. [PMID: 38964508 DOI: 10.1016/j.arr.2024.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 06/05/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Circadian rhythms are biological rhythms that originate from the "master circadian clock," called the suprachiasmatic nucleus (SCN). SCN orchestrates the circadian rhythms using light as a chief zeitgeber, enabling humans to synchronize their daily physio-behavioral activities with the Earth's light-dark cycle. However, chronic/ irregular photic disturbances from the retina via the retinohypothalamic tract (RHT) can disrupt the amplitude and the expression of clock genes, such as the period circadian clock 2, causing circadian rhythm disruption (CRd) and associated neuropathologies. The present review discusses neuromodulation across the RHT originating from retinal photic inputs and modulation offered by endocannabinoids as a function of mitigation of the CRd and associated neuro-dysfunction. Literature indicates that cannabinoid agonists alleviate the SCN's ability to get entrained to light by modulating the activity of its chief neurotransmitter, i.e., γ-aminobutyric acid, thus preventing light-induced disruption of activity rhythms in laboratory animals. In the retina, endocannabinoid signaling modulates the overall gain of the retinal ganglion cells by regulating the membrane currents (Ca2+, K+, and Cl- channels) and glutamatergic neurotransmission of photoreceptors and bipolar cells. Additionally, endocannabinoids signalling also regulate the high-voltage-activated Ca2+ channels to mitigate the retinal ganglion cells and intrinsically photosensitive retinal ganglion cells-mediated glutamate release in the SCN, thus regulating the RHT-mediated light stimulation of SCN neurons to prevent excitotoxicity. As per the literature, cannabinoid receptors 1 and 2 are becoming newer targets in drug discovery paradigms, and the involvement of endocannabinoids in light-induced CRd through the RHT may possibly mitigate severe neuropathologies.
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Affiliation(s)
- Deepak Kumar
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
| | - Bareera Khan
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India
| | - Yagmur Okcay
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Çağıl Önal Sis
- University of Health Sciences Gulhane Faculty of Pharmacy Department of Pharmacology, Turkey.
| | - Aya Abdallah
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Fiona Murray
- Institute of Medical Science, University of Aberdeen, Aberdeen, Scotland.
| | - Ashish Sharma
- School of Medicine, Washington University, St. Louis, USA
| | - Maiko Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Rajeev Taliyan
- Department of Pharmacy, Birla Institute of Technology Science, Pilani, Rajasthan 333301, India.
| | - Thomas Heinbockel
- Howard University College of Medicine, Department of Anatomy, Washington, DC 20059, USA
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University, Brookings, SD, USA.
| | - Rohit Goyal
- Department of Neuropharmacology, School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, HP 173229, India.
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2
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Estay SF, Morales-Moraga C, Vielma AH, Palacios-Muñoz A, Chiu CQ, Chávez AE. Non-canonical type 1 cannabinoid receptor signaling regulates night visual processing in the inner rat retina. iScience 2024; 27:109920. [PMID: 38799553 PMCID: PMC11126983 DOI: 10.1016/j.isci.2024.109920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/18/2024] [Accepted: 05/03/2024] [Indexed: 05/29/2024] Open
Abstract
Type 1 cannabinoid receptors (CB1Rs) are expressed in major retinal neurons within the rod-pathway suggesting a role in regulating night visual processing, but the underlying mechanisms remain poorly understood. Using acute rat retinal slices, we show that CB1R activation reduces glutamate release from rod bipolar cell (RBC) axon terminals onto AII and A17 amacrine cells through a pathway that requires exchange proteins directly activated by cAMP (EPAC1/2) signaling. Consequently, CB1R activation abrogates reciprocal GABAergic feedback inhibition from A17 amacrine cells. Moreover, the activation of CB1Rs in vivo enhances and prolongs the time course of the dim-light rod-driven visual responses, an effect that was eliminated when both GABAA and GABAC receptors were blocked. Altogether, our findings underscore a non-canonical mechanism by which cannabinoid signaling regulates RBC dyad synapses in the inner retina to regulate dim-light visual responses to fine-tune night vision.
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Affiliation(s)
- Sebastián F. Estay
- Programa de Doctorado en Ciencias, Mención Neurociencia, Valparaíso 2340000, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Camila Morales-Moraga
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Alex H. Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Angelina Palacios-Muñoz
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Chiayu Q. Chiu
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Andrés E. Chávez
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
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3
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Tempone MH, Borges-Martins VP, César F, Alexandrino-Mattos DP, de Figueiredo CS, Raony Í, dos Santos AA, Duarte-Silva AT, Dias MS, Freitas HR, de Araújo EG, Ribeiro-Resende VT, Cossenza M, P. Silva H, P. de Carvalho R, Ventura ALM, Calaza KC, Silveira MS, Kubrusly RCC, de Melo Reis RA. The Healthy and Diseased Retina Seen through Neuron-Glia Interactions. Int J Mol Sci 2024; 25:1120. [PMID: 38256192 PMCID: PMC10817105 DOI: 10.3390/ijms25021120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
The retina is the sensory tissue responsible for the first stages of visual processing, with a conserved anatomy and functional architecture among vertebrates. To date, retinal eye diseases, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, glaucoma, and others, affect nearly 170 million people worldwide, resulting in vision loss and blindness. To tackle retinal disorders, the developing retina has been explored as a versatile model to study intercellular signaling, as it presents a broad neurochemical repertoire that has been approached in the last decades in terms of signaling and diseases. Retina, dissociated and arranged as typical cultures, as mixed or neuron- and glia-enriched, and/or organized as neurospheres and/or as organoids, are valuable to understand both neuronal and glial compartments, which have contributed to revealing roles and mechanisms between transmitter systems as well as antioxidants, trophic factors, and extracellular matrix proteins. Overall, contributions in understanding neurogenesis, tissue development, differentiation, connectivity, plasticity, and cell death are widely described. A complete access to the genome of several vertebrates, as well as the recent transcriptome at the single cell level at different stages of development, also anticipates future advances in providing cues to target blinding diseases or retinal dysfunctions.
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Affiliation(s)
- Matheus H. Tempone
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Vladimir P. Borges-Martins
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Felipe César
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Dio Pablo Alexandrino-Mattos
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Camila S. de Figueiredo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Ícaro Raony
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (Í.R.); (H.R.F.)
| | - Aline Araujo dos Santos
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Aline Teixeira Duarte-Silva
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Mariana Santana Dias
- Laboratory of Gene Therapy and Viral Vectors, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.S.D.); (H.P.S.)
| | - Hércules Rezende Freitas
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (Í.R.); (H.R.F.)
| | - Elisabeth G. de Araújo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
- National Institute of Science and Technology on Neuroimmunomodulation—INCT-NIM, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21040-360, Brazil
| | - Victor Tulio Ribeiro-Resende
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Marcelo Cossenza
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Hilda P. Silva
- Laboratory of Gene Therapy and Viral Vectors, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.S.D.); (H.P.S.)
| | - Roberto P. de Carvalho
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Ana L. M. Ventura
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Karin C. Calaza
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Mariana S. Silveira
- Laboratory for Investigation in Neuroregeneration and Development, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil;
| | - Regina C. C. Kubrusly
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Ricardo A. de Melo Reis
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
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Pasquaré SJ, Chamorro-Aguirre E, Gaveglio VL. The endocannabinoid system in the visual process. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2022. [DOI: 10.1016/j.jpap.2022.100159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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5
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Cao J, Mangel SC. Interactions of cone cannabinoid CB1 and dopamine D4 receptors increase day/night difference in rod-cone gap junction coupling in goldfish retina. J Physiol 2021; 599:4085-4100. [PMID: 34252195 DOI: 10.1113/jp281308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/30/2021] [Indexed: 01/16/2023] Open
Abstract
KEY POINTS Although cone and rod photoreceptor cells in the retina have a type of cannabinoid receptor called a CB1 receptor, little is known about how cannabinoids, the active component in marijuana, affect retinal function. Studies have shown that a circadian (24-h) clock in the retina uses dopamine receptors, which are also on photoreceptors, to regulate gap junctions (a type of cell-to-cell communication) between rods and cones, so that they are functional (open) at night but closed in the day. We show that CB1 receptors have opposite effects on rod-cone gap junctions in day and night, decreasing communication in the day when dopamine receptors are active and increasing communication when dopamine receptors are inactive. CB1 and dopamine receptors thus work together to enhance the day/night difference in rod-cone gap junction communication. The increased rod-cone communication at night due to cannabinoid CB1 receptors may help improve night vision. ABSTRACT Cannabinoid CB1 receptors and dopamine D4 receptors in the brain form receptor complexes that interact but the physiological function of these interactions in intact tissue remains unclear. In vertebrate retina, rods and cones, which are connected by gap junctions, express both CB1 and D4 receptors. Because the retinal circadian clock uses cone D4 receptors to decrease rod-cone gap junction coupling in the day and to increase it at night, we studied whether an interaction between cone CB1 and D4 receptors increases the day/night difference in rod-cone coupling compared to D4 receptors acting alone. Using electrical recording and injections of Neurobiotin tracer into individual cones in intact goldfish retinas, we found that SR141716A (a CB1 receptor antagonist) application alone in the day increased both the extent of rod-cone tracer coupling and rod input to cones, which reaches cones via open gap junctions. Conversely, SR141716A application alone at night or SR141716A application in the day following 30-min spiperone (a D4 receptor antagonist) application decreased both rod-cone tracer coupling and rod input to cones. These results show that endogenous activation of cone CB1 receptors decreases rod-cone coupling in the day when D4 receptors are activated but increases it at night when D4 receptors are not activated. Therefore, the D4 receptor-dependent day/night switch in the effects of CB1 receptor activation results in an enhancement of the day/night difference in rod-cone coupling. This synergistic interaction increases detection of very dim large objects at night and fine spatial details in the day.
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Affiliation(s)
- Jiexin Cao
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, Ohio State University, Columbus, OH, USA.,Department of Neuroscience, Ohio State University College of Medicine, Columbus, OH, USA
| | - Stuart C Mangel
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, Ohio State University, Columbus, OH, USA.,Department of Neuroscience, Ohio State University College of Medicine, Columbus, OH, USA
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6
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Heinbockel T, Straiker A. Cannabinoids Regulate Sensory Processing in Early Olfactory and Visual Neural Circuits. Front Neural Circuits 2021; 15:662349. [PMID: 34305536 PMCID: PMC8294086 DOI: 10.3389/fncir.2021.662349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/11/2021] [Indexed: 12/25/2022] Open
Abstract
Our sensory systems such as the olfactory and visual systems are the target of neuromodulatory regulation. This neuromodulation starts at the level of sensory receptors and extends into cortical processing. A relatively new group of neuromodulators includes cannabinoids. These form a group of chemical substances that are found in the cannabis plant. Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main cannabinoids. THC acts in the brain and nervous system like the chemical substances that our body produces, the endogenous cannabinoids or endocannabinoids, also nicknamed the brain's own cannabis. While the function of the endocannabinoid system is understood fairly well in limbic structures such as the hippocampus and the amygdala, this signaling system is less well understood in the olfactory pathway and the visual system. Here, we describe and compare endocannabinoids as signaling molecules in the early processing centers of the olfactory and visual system, the olfactory bulb, and the retina, and the relevance of the endocannabinoid system for synaptic plasticity.
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Affiliation(s)
- Thomas Heinbockel
- Department of Anatomy, Howard University College of Medicine, Washington, DC, United States
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
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7
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Schwitzer T, Henrion ML, Sarre D, Albuisson E, Angioi-Duprez K, Giersch A, Lalanne L, Schwan R, Laprevote V. Spatial localization of retinal anomalies in regular cannabis users: The relevance of the multifocal electroretinogram. Schizophr Res 2020; 219:56-61. [PMID: 30696610 DOI: 10.1016/j.schres.2019.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/10/2019] [Accepted: 01/14/2019] [Indexed: 11/17/2022]
Abstract
Widely used in industrialized countries, cannabis is a neuromodulator substance. The cannabinoid system is present at critical stages of retinal processing. We have recently shown a delay in bipolar and ganglion cell responses in regular cannabis users, as observed using flash (fERG) and pattern (PERG) electroretinogram. Although the results obtained during these tests provide information about global retinal responses, they do not give any indication about the spatial localization of the anomalies that were detected. The latter may be analyzed, however, by means of multifocal electroretinogram (mfERG). We recorded the mfERG responses in 49 regular cannabis users and 21 healthy subjects. The amplitudes and implicit times of the mfERG N1, P1 and N2 waves were recorded. The results showed that in regular cannabis users: in the <2° region, a significant increase in the N2 implicit time (p = 0.037); in the 2-5° region, a significant increase in the N2 (p = 0.018) and P1 (p = 0.046) implicit times; in the 5-10° region, a significant increase in the P1 (p = 0.006) and N1 (p = 0.034) implicit times; and in the 10-15° region, a significant increase in the P1 implicit time (p = 0.014). An isolated decrease in the N1 amplitude in the 2-5° region (p = 0.044) was also found. This indicates that there is a delay in the transmission of visual information from the central retina to the near periphery in cannabis users suggesting potential alterations in precise and color vision.
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Affiliation(s)
- Thomas Schwitzer
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France.
| | - Marie-Laure Henrion
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
| | - Daphné Sarre
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
| | - Eliane Albuisson
- Pôle S(2)R, PARC, BIOBASE, CHRU Nancy, Vandoeuvre lès Nancy, France; Université de Lorraine, Faculté de Médecine, InSciDens, Vandoeuvre lès Nancy, France; CNRS, Institut Elie Cartan de Lorraine, UMR 7502, Vandoeuvre-lès-Nancy F-54506,France
| | | | - Anne Giersch
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Laurence Lalanne
- INSERM 1114, Department of addictology, FMTS (federation de médecine translationnelle) University Hospital of Strasbourg
| | - Raymund Schwan
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Maison des Addictions, CHRU Nancy, Nancy, France
| | - Vincent Laprevote
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
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8
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Van Hook MJ, Nawy S, Thoreson WB. Voltage- and calcium-gated ion channels of neurons in the vertebrate retina. Prog Retin Eye Res 2019; 72:100760. [PMID: 31078724 PMCID: PMC6739185 DOI: 10.1016/j.preteyeres.2019.05.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
In this review, we summarize studies investigating the types and distribution of voltage- and calcium-gated ion channels in the different classes of retinal neurons: rods, cones, horizontal cells, bipolar cells, amacrine cells, interplexiform cells, and ganglion cells. We discuss differences among cell subtypes within these major cell classes, as well as differences among species, and consider how different ion channels shape the responses of different neurons. For example, even though second-order bipolar and horizontal cells do not typically generate fast sodium-dependent action potentials, many of these cells nevertheless possess fast sodium currents that can enhance their kinetic response capabilities. Ca2+ channel activity can also shape response kinetics as well as regulating synaptic release. The L-type Ca2+ channel subtype, CaV1.4, expressed in photoreceptor cells exhibits specific properties matching the particular needs of these cells such as limited inactivation which allows sustained channel activity and maintained synaptic release in darkness. The particular properties of K+ and Cl- channels in different retinal neurons shape resting membrane potentials, response kinetics and spiking behavior. A remaining challenge is to characterize the specific distributions of ion channels in the more than 100 individual cell types that have been identified in the retina and to describe how these particular ion channels sculpt neuronal responses to assist in the processing of visual information by the retina.
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Affiliation(s)
- Matthew J Van Hook
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Scott Nawy
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA
| | - Wallace B Thoreson
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA.
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Middleton TP, Huang JY, Protti DA. Cannabinoids Modulate Light Signaling in ON-Sustained Retinal Ganglion Cells of the Mouse. Front Neural Circuits 2019; 13:37. [PMID: 31164809 PMCID: PMC6536650 DOI: 10.3389/fncir.2019.00037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/02/2019] [Indexed: 11/13/2022] Open
Abstract
The sole output of the retina to the brain is a signal that results from the integration of excitatory and inhibitory synaptic inputs at the level of retinal ganglion cells (RGCs). Endogenous cannabinoids (eCBs) are found throughout the central nervous system where they modulate synaptic excitability. Cannabinoid receptors and their ligands have been localized to most retinal neurons in mammals, yet their impact on retinal processing is not well known. Here, we set out to investigate the role of the cannabinoid system in retinal signaling using electrophysiological recordings from ON-sustained (ON-S) RGCs that displayed morphological and physiological signatures of ON alpha RGCs in dark adapted mouse retina. We studied the effect of the cannabinoid agonist WIN55212-2 and the inverse agonist AM251 on the spatial tuning of ON-S RGCs. WIN55212-2 significantly reduced their spontaneous spiking activity and responses to optimal spot size as well as altered their spatial tuning by reducing light driven excitatory and inhibitory inputs to RGCs. AM251 produced the opposite effect, increasing spontaneous spiking activity and peak response as well as increasing inhibitory and excitatory inputs. In addition, AM251 sharpened the spatial tuning of ON-S RGCs by increasing the inhibitory effect of the surround. These results demonstrate the presence of a functional cannabinergic system in the retina as well as sensitivity of ON-RGCs to cannabinoids. These results reveal a neuromodulatory system that can regulate the sensitivity and excitability of retinal synapses in a dynamic, activity dependent manner and that endocannabinoids may play a significant role in retinal processing.
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Affiliation(s)
- Terence Peter Middleton
- Discipline of Physiology, The University of Sydney, Sydney, NSW, Australia.,Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Jin Yu Huang
- Bosch Institute, The University of Sydney, Sydney, NSW, Australia.,Discipline of Biomedical Science, The University of Sydney, Sydney, NSW, Australia
| | - Dario Alejandro Protti
- Discipline of Physiology, The University of Sydney, Sydney, NSW, Australia.,Bosch Institute, The University of Sydney, Sydney, NSW, Australia
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10
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Zhu H, Xiang HC, Li HP, Lin LX, Hu XF, Zhang H, Meng WY, Liu L, Chen C, Shu Y, Zhang RY, Zhang P, Si JQ, Li M. Inhibition of GABAergic Neurons and Excitation of Glutamatergic Neurons in the Ventrolateral Periaqueductal Gray Participate in Electroacupuncture Analgesia Mediated by Cannabinoid Receptor. Front Neurosci 2019; 13:484. [PMID: 31156369 PMCID: PMC6533898 DOI: 10.3389/fnins.2019.00484] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/29/2019] [Indexed: 01/26/2023] Open
Abstract
Although electroacupuncture (EA) has become a worldwide practice, little is understood about its precise target in the central nervous system (CNS) and the cell type-specific analgesia mechanism. In the present study, we found that EA has significant antinociceptive effects both in inflammatory and neuropathic pain models. Chemogenetic inhibition of GABAergic neurons in the ventrolateral periaqueductal gray (vlPAG) replicated the effects of EA, whereas the combination of chemogenetic activation of GABAergic neurons and chemogenetic inhibition of glutamatergic neurons in the vlPAG was needed to reverse the effects of EA. Specifically knocking out CB1 receptors on GABAergic neurons in the vlPAG abolished the EA effect on pain hypersensitivity, while specifically knocking out CB1 receptors on glutamatergic neurons attenuated only a small portion of the EA effect. EA synchronously inhibits GABAergic neurons and activates glutamatergic neurons in the vlPAG through CB1 receptors to produce EA-induced analgesia. The CB1 receptors on GABAergic neurons localized in the vlPAG was the basis of the EA effect on pain hypersensitivity. This study provides new experimental evidence that EA can bidirectionally regulate GABAergic neurons and glutamatergic neurons via the CB1 receptors of the vlPAG to produce analgesia effects.
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Affiliation(s)
- He Zhu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.,Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Hong-Chun Xiang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Ping Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Li-Xue Lin
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Fei Hu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Wang-Yang Meng
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Lu Liu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Chao Chen
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yang Shu
- Department of Central Laboratory, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ru-Yue Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Pei Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jun-Qiang Si
- Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Man Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
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11
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The Endocannabinoid System Is Present in Rod Outer Segments from Retina and Is Modulated by Light. Mol Neurobiol 2019; 56:7284-7295. [PMID: 31016476 DOI: 10.1007/s12035-019-1603-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
The aim of the present research was to evaluate if the endocannabinoid system (enzymes and receptors) could be modulated by light in rod outer segment (ROS) from bovine retina. First, we analyzed endocannabinoid 2-arachidonoylglycerol (2-AG) metabolism in purified ROS obtained from dark-adapted (DROS) or light-adapted (LROS) retinas. To this end, diacylglycerol lipase (DAGL), monoacylglycerol lipase (MAGL), and lysophosphatidate phosphohydrolase (LPAP) enzymatic activities were analyzed using radioactive substrates. The protein content of these enzymes and of the receptors to which cannabinoids bind was determined by immunoblotting under light stimulus. Our results indicate that whereas DAGL and MAGL activities were stimulated in retinas exposed to light, no changes were observed in LPAP activity. Interestingly, the protein content of the main enzymes involved in 2-AG metabolism, phospholipase C β1 (PLCβ1), and DAGLα (synthesis), and MAGL (hydrolysis), was also modified by light. PLCβ1 content was increased, while that of lipases was decreased. On the other hand, light produced an increase in the cannabinoid receptors CB1 and CB2 and a decrease in GPR55 protein levels. Taken together, our results indicate that the endocannabinoid system (enzymes and receptors) depends on the illumination state of the retina, suggesting that proteins related to phototransduction phenomena could be involved in the effects observed.
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Lax P, Kutsyr O, Esquiva G, Altavilla C, Maneu V, Cuenca N. Cannabinoid-mediated retinal rescue correlates with improved circadian parameters in retinal dystrophic rats. Exp Eye Res 2019; 180:192-199. [DOI: 10.1016/j.exer.2018.12.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/13/2018] [Accepted: 12/30/2018] [Indexed: 11/15/2022]
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Schwitzer T, Schwan R, Angioi-Duprez K, Lalanne L, Giersch A, Laprevote V. Cannabis use and human retina: The path for the study of brain synaptic transmission dysfunctions in cannabis users. Neurosci Biobehav Rev 2019; 106:11-22. [PMID: 30773228 DOI: 10.1016/j.neubiorev.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 11/08/2018] [Accepted: 12/02/2018] [Indexed: 01/01/2023]
Abstract
Owing to the difficulty of obtaining direct access to the functioning brain, new approaches are needed for the indirect exploration of brain disorders in neuroscience research. Due to its embryonic origin, the retina is part of the central nervous system and is well suited to the investigation of neurological functions in psychiatric and addictive disorders. In this review, we focus on cannabis use, which is a crucial public health challenge, since cannabis is one of the most widely used addictive drugs in industrialized countries. We first explain why studying retinal function is relevant when exploring the effects of cannabis use on brain function. Next, we describe both the retinal electrophysiological measurements and retinal dysfunctions observed after acute and regular cannabis use. We then discuss how these retinal dysfunctions may inform brain synaptic transmission abnormalities. Finally, we present various directions for future research on the neurotoxic effects of cannabis use.
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Affiliation(s)
- Thomas Schwitzer
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France.
| | - Raymund Schwan
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Maison des Addictions, CHRU Nancy, Nancy, France
| | | | - Laurence Lalanne
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Pôle de Psychiatrie Santé Mentale et Addictologie, Fédération de Médecine Translationnelle de Strasbourg, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Anne Giersch
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Vincent Laprevote
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
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14
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Pangrsic T, Singer JH, Koschak A. Voltage-Gated Calcium Channels: Key Players in Sensory Coding in the Retina and the Inner Ear. Physiol Rev 2019; 98:2063-2096. [PMID: 30067155 DOI: 10.1152/physrev.00030.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcium influx through voltage-gated Ca (CaV) channels is the first step in synaptic transmission. This review concerns CaV channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the CaV channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of CaV channels at presynaptic, ribbon-type active zones, because the spatial relationship between CaV channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, CaV1.3, and CaV1.4 channels or their protein modulatory elements.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Joshua H Singer
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Alexandra Koschak
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
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15
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Borowska-Fielding J, Murataeva N, Smith B, Szczesniak AM, Leishman E, Daily L, Toguri JT, Hillard CJ, Romero J, Bradshaw H, Kelly MEM, Straiker A. Revisiting cannabinoid receptor 2 expression and function in murine retina. Neuropharmacology 2018; 141:21-31. [PMID: 30121200 DOI: 10.1016/j.neuropharm.2018.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/15/2018] [Accepted: 08/05/2018] [Indexed: 01/12/2023]
Abstract
The cannabinoid receptor CB2 plays a significant role in the regulation of immune function whereas neuronal expression remains a subject of contention. Multiple studies have described CB2 in retina and a recent study showed that CB2 deletion altered retinal visual processing. We revisited CB2 expression using immunohistochemistry and a recently developed CB2-eGFP reporter mouse. We examined the consequence of acute vs. prolonged CB2 deactivation on the electroretinogram (ERG) responses. We also examined lipidomics in CB2 knockout mice and potential changes in microglia using Scholl analysis. Consistent with a published report, in CB2 receptor knockout mice see an increased ERG scotopic a-wave, as well as stronger responses in dark adapted cone-driven ON bipolar cells and, to a lesser extent cone-driven ON bipolar cells early in light adaptation. Significantly, however, acute block with CB2 antagonist, AM630, did not mimic the results observed in the CB2 knockout mice whereas chronic (7 days) block did. Immunohistochemical studies show no CB2 in retina under non-pathological conditions, even with published antibodies. Retinal CB2-eGFP reporter signal is minimal under baseline conditions but upregulated by intraocular injection of either LPS or carrageenan. CB2 knockout mice see modest declines in a broad spectrum of cannabinoid-related lipids. The numbers and morphology of microglia were unaltered. In summary minimal CB2 expression is seen in healthy retina. CB2 appears to be upregulated under pathological conditions. Previously reported functional consequences of CB2 deletion are an adaptive response to prolonged blockade of these receptors. CB2 therefore impacts retinal signaling but perhaps in an indirect, potentially extra-ocular fashion.
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Affiliation(s)
| | - Natalia Murataeva
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Ben Smith
- Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | | | - Emma Leishman
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Laura Daily
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - J Thomas Toguri
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Cecelia J Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Julian Romero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Heather Bradshaw
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Melanie E M Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada; Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada; Anesthesia, Dalhousie University, Halifax, NS, Canada
| | - Alex Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA.
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16
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Rapino C, Tortolani D, Scipioni L, Maccarrone M. Neuroprotection by (endo)Cannabinoids in Glaucoma and Retinal Neurodegenerative Diseases. Curr Neuropharmacol 2018; 16:959-970. [PMID: 28738764 PMCID: PMC6120105 DOI: 10.2174/1570159x15666170724104305] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/14/2017] [Accepted: 07/21/2017] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Emerging neuroprotective strategies are being explored to preserve the retina from degeneration, that occurs in eye pathologies like glaucoma, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosa. Incidentally, neuroprotection of retina is a defending mechanism designed to prevent or delay neuronal cell death, and to maintain neural function following an initial insult, thus avoiding loss of vision. METHODS Numerous studies have investigated potential neuroprotective properties of plant-derived phytocannabinoids, as well as of their endogenous counterparts collectively termed endocannabinoids (eCBs), in several degenerative diseases of the retina. eCBs are a group of neuromodulators that, mainly by activating G protein-coupled type-1 and type-2 cannabinoid (CB1 and CB2) receptors, trigger multiple signal transduction cascades that modulate central and peripheral cell functions. A fine balance between biosynthetic and degrading enzymes that control the right concentration of eCBs has been shown to provide neuroprotection in traumatic, ischemic, inflammatory and neurotoxic damage of the brain. RESULTS Since the existence of eCBs and their binding receptors was documented in the retina of numerous species (from fishes to primates), their involvement in the visual processing has been demonstrated, more recently with a focus on retinal neurodegeneration and neuroprotection. CONCLUSION The aim of this review is to present a modern view of the endocannabinoid system, in order to discuss in a better perspective available data from preclinical studies on the use of eCBs as new neuroprotective agents, potentially useful to prevent glaucoma and retinal neurodegenerative diseases.
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Affiliation(s)
- Cinzia Rapino
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
| | | | | | - Mauro Maccarrone
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
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17
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Grassmeyer JJ, Thoreson WB. Synaptic Ribbon Active Zones in Cone Photoreceptors Operate Independently from One Another. Front Cell Neurosci 2017; 11:198. [PMID: 28744203 PMCID: PMC5504102 DOI: 10.3389/fncel.2017.00198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/26/2017] [Indexed: 12/04/2022] Open
Abstract
Cone photoreceptors depolarize in darkness to release glutamate-laden synaptic vesicles. Essential to release is the synaptic ribbon, a structure that helps organize active zones by clustering vesicles near proteins that mediate exocytosis, including voltage-gated Ca2+ channels. Cone terminals have many ribbon-style active zones at which second-order neurons receive input. We asked whether there are functionally significant differences in local Ca2+ influx among ribbons in individual cones. We combined confocal Ca2+ imaging to measure Ca2+ influx at individual ribbons and patch clamp recordings to record whole-cell ICa in salamander cones. We found that the voltage for half-maximal activation (V50) of whole cell ICa in cones averaged −38.1 mV ± 3.05 mV (standard deviation [SD]), close to the cone membrane potential in darkness of ca. −40 mV. Ca2+ signals at individual ribbons varied in amplitude from one another and showed greater variability in V50 values than whole-cell ICa, suggesting that Ca2+ signals can differ significantly among ribbons within cones. After accounting for potential sources of technical variability in measurements of Ca2+ signals and for contributions from cone-to-cone differences in ICa, we found that the variability in V50 values for ribbon Ca2+ signals within individual cones showed a SD of 2.5 mV. Simulating local differences in Ca2+ channel activity at two ribbons by shifting the V50 value of ICa by ±2.5 mV (1 SD) about the mean suggests that when the membrane depolarizes to −40 mV, two ribbons could experience differences in Ca2+ influx of >45%. Further evidence that local Ca2+ changes at ribbons can be regulated independently was obtained in experiments showing that activation of inhibitory feedback from horizontal cells (HCs) to cones in paired recordings changed both amplitude and V50 of Ca2+ signals at individual ribbons. By varying the strength of synaptic output, differences in voltage dependence and amplitude of Ca2+ signals at individual ribbons shape the information transmitted from cones to downstream neurons in vision.
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Affiliation(s)
- Justin J Grassmeyer
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical CenterOmaha, NE, United States.,Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, University of Nebraska Medical CenterOmaha, NE, United States
| | - Wallace B Thoreson
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical CenterOmaha, NE, United States.,Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, University of Nebraska Medical CenterOmaha, NE, United States
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18
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Cannabinoid CB1 and CB2 receptors differentially modulate L- and T-type Ca 2+ channels in rat retinal ganglion cells. Neuropharmacology 2017; 124:143-156. [PMID: 28431968 DOI: 10.1016/j.neuropharm.2017.04.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/15/2017] [Accepted: 04/17/2017] [Indexed: 01/09/2023]
Abstract
Endocannabinoid signaling system is involved in regulating multiple neuronal functions in the central nervous system by activating G-protein coupled cannabinoid CB1 and CB2 receptors (CB1Rs and CB2Rs). Growing evidence has shown that CB1Rs and CB2Rs are extensively expressed in retinal ganglion cells (RGCs). Here, modulation of L- and T-types Ca2+ channels by activating CB1Rs and CB2Rs in RGCs was investigated. Triple immunofluorescent staining showed that L-type subunit CaV1.2 was co-localized with T-type subunits (CaV3.1, CaV3.2 and CaV3.3) in rat RGCs. In acutely isolated rat RGCs, the CB1R agonist WIN55212-2 suppressed both peak and steady-state Ca2+ currents in a dose-dependent manner, with IC50 being 9.6 μM and 8.4 μM, respectively. It was further shown that activation of CB1Rs by WIN55212-2 or ACEA, another CB1R agonist, significantly suppressed both L- and T-type Ca2+ currents, and shifted inactivation curve of T-type one toward hyperpolarization direction. While the effect on L-type Ca2+ channels was mediated by intracellular cAMP/protein kinase A (PKA), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling pathways, only CaMKII signaling pathway was involved in the effect on T-type Ca2+ channels. Furthermore, CB65 and HU308, two specific CB2R agonists, significantly suppressed T-type Ca2+ channels, which was mediated by intracellular cAMP/PKA and CaMKII signaling pathways, but had no effect on L-type channels. These results imply that endogenous cannabinoids may modulate the excitability and the output of RGCs by differentially suppressing the activity of L- and T-type Ca2+ channels through activation of CB1Rs and CB2Rs. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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A Presynaptic Group III mGluR Recruits Gβγ/SNARE Interactions to Inhibit Synaptic Transmission by Cone Photoreceptors in the Vertebrate Retina. J Neurosci 2017; 37:4618-4634. [PMID: 28363980 DOI: 10.1523/jneurosci.2948-16.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/21/2022] Open
Abstract
G-protein βγ subunits (Gβγ) interact with presynaptic proteins and regulate neurotransmitter release downstream of Ca2+ influx. To accomplish their roles in sensory signaling, photoreceptor synapses use specialized presynaptic proteins that support neurotransmission at active zone structures known as ribbons. While several G-protein coupled receptors (GPCRs) influence synaptic transmission at ribbon synapses of cones and other retinal neurons, it is unknown whether Gβγ contributes to these effects. We tested whether activation of one particular GPCR, a metabotropic glutamate receptor (mGluR), can reduce cone synaptic transmission via Gβγ in tiger salamander retinas. In recordings from horizontal cells, we found that an mGluR agonist (L-AP4) reduced cone-driven light responses and mEPSC frequency. In paired recordings of cones and horizontal cells, L-AP4 slightly reduced cone ICa (∼10%) and caused a larger reduction in cone-driven EPSCs (∼30%). Proximity ligation assay revealed direct interactions between SNAP-25 and Gβγ subunits in retinal synaptic layers. Pretreatment with the SNAP-25 cleaving protease BoNT/A inhibited L-AP4 effects on synaptic transmission, as did introduction of a peptide derived from the SNAP-25 C terminus. Introducing Gβγ subunits directly into cones reduced EPSC amplitude. This effect was inhibited by BoNT/A, supporting a role for Gβγ/SNAP-25 interactions. However, the mGluR-dependent reduction in ICa was not mimicked by Gβγ, indicating that this effect was independent of Gβγ. The finding that synaptic transmission at cone ribbon synapses is regulated by Gβγ/SNAP-25 interactions indicates that these mechanisms are shared by conventional and ribbon-type synapses. Gβγ liberated from other photoreceptor GPCRs is also likely to regulate synaptic transmission.SIGNIFICANCE STATEMENT Dynamic regulation of synaptic transmission by presynaptic G-protein coupled receptors shapes information flow through neural circuits. At the first synapse in the visual system, presynaptic metabotropic glutamate receptors (mGluRs) regulate cone photoreceptor synaptic transmission, although the mechanisms and functional impact of this are unclear. We show that mGluRs regulate light response encoding across the cone synapse, accomplished in part by triggering G-protein βγ subunits (Gβγ) interactions with SNAP-25, a core component of the synaptic vesicle fusion machinery. In addition to revealing a role in visual processing, this provides the first demonstration that Gβγ/SNAP-25 interactions regulate synaptic function at a ribbon-type synapse, contributing to an emerging picture of the ubiquity of Gβγ/SNARE interactions in regulating synaptic transmission throughout the nervous system.
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Zhong W, Picca AJ, Lee AS, Darmani NA. Ca2+ signaling and emesis: Recent progress and new perspectives. Auton Neurosci 2017; 202:18-27. [DOI: 10.1016/j.autneu.2016.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 02/07/2023]
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Cannabinoid Receptors CB1 and CB2 Modulate the Electroretinographic Waves in Vervet Monkeys. Neural Plast 2016; 2016:1253245. [PMID: 27069692 PMCID: PMC4812474 DOI: 10.1155/2016/1253245] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/21/2016] [Accepted: 01/26/2016] [Indexed: 11/17/2022] Open
Abstract
The expression patterns of the cannabinoid receptor type 1 (CB1R) and the cannabinoid receptor type 2 (CB2R) are well documented in rodents and primates. In vervet monkeys, CB1R is present in the retinal neurons (photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells) and CB2R is exclusively found in the retinal glia (Müller cells). However, the role of these cannabinoid receptors in normal primate retinal function remains elusive. Using full-field electroretinography in adult vervet monkeys, we recorded changes in neural activity following the blockade of CB1R and CB2R by the intravitreal administration of their antagonists (AM251 and AM630, resp.) in photopic and scotopic conditions. Our results show that AM251 increases the photopic a-wave amplitude at high flash intensities, whereas AM630 increases the amplitude of both the photopic a- and b-waves. In scotopic conditions, both blockers increased the b-wave amplitude but did not change the a-wave amplitude. These findings suggest an important role of CB1R and CB2R in primate retinal function.
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The Endocannabinoid System in the Retina: From Physiology to Practical and Therapeutic Applications. Neural Plast 2016; 2016:2916732. [PMID: 26881099 PMCID: PMC4736597 DOI: 10.1155/2016/2916732] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/23/2015] [Indexed: 01/11/2023] Open
Abstract
Cannabis is one of the most prevalent drugs used in industrialized countries. The main effects of Cannabis are mediated by two major exogenous cannabinoids: ∆9-tetrahydroxycannabinol and cannabidiol. They act on specific endocannabinoid receptors, especially types 1 and 2. Mammals are endowed with a functional cannabinoid system including cannabinoid receptors, ligands, and enzymes. This endocannabinoid signaling pathway is involved in both physiological and pathophysiological conditions with a main role in the biology of the central nervous system. As the retina is a part of the central nervous system due to its embryonic origin, we aim at providing the relevance of studying the endocannabinoid system in the retina. Here, we review the distribution of the cannabinoid receptors, ligands, and enzymes in the retina and focus on the role of the cannabinoid system in retinal neurobiology. This review describes the presence of the cannabinoid system in critical stages of retinal processing and its broad involvement in retinal neurotransmission, neuroplasticity, and neuroprotection. Accordingly, we support the use of synthetic cannabinoids as new neuroprotective drugs to prevent and treat retinal diseases. Finally, we argue for the relevance of functional retinal measures in cannabis users to evaluate the impact of cannabis use on human retinal processing.
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Endogenous and Synthetic Cannabinoids as Therapeutics in Retinal Disease. Neural Plast 2016; 2016:8373020. [PMID: 26881135 PMCID: PMC4736800 DOI: 10.1155/2016/8373020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/16/2015] [Accepted: 12/01/2015] [Indexed: 11/25/2022] Open
Abstract
The functional significance of cannabinoids in ocular physiology and disease has been reported some decades ago. In the early 1970s, subjects who smoked Cannabis sativa developed lower intraocular pressure (IOP). This led to the isolation of phytocannabinoids from this plant and the study of their therapeutic effects in glaucoma. The main treatment of this disease to date involves the administration of drugs mediating either the decrease of aqueous humour synthesis or the increase of its outflow and thus reduces IOP. However, the reduction of IOP is not sufficient to prevent visual field loss. Retinal diseases, such as glaucoma and diabetic retinopathy, have been defined as neurodegenerative diseases and characterized by ischemia-induced excitotoxicity and loss of retinal neurons. Therefore, new therapeutic strategies must be applied in order to target retinal cell death, reduction of visual acuity, and blindness. The aim of the present review is to address the neuroprotective and therapeutic potential of cannabinoids in retinal disease.
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Yang W, Li Q, Wang SY, Gao F, Qian WJ, Li F, Ji M, Sun XH, Miao Y, Wang Z. Cannabinoid receptor agonists modulate calcium channels in rat retinal müller cells. Neuroscience 2016; 313:213-24. [DOI: 10.1016/j.neuroscience.2015.11.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/10/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022]
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Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain. Neural Plast 2015; 2016:9247057. [PMID: 26839718 PMCID: PMC4709729 DOI: 10.1155/2016/9247057] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/24/2015] [Accepted: 09/27/2015] [Indexed: 12/16/2022] Open
Abstract
Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system. Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function. In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing. The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far. It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells. The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.
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Van Hook MJ, Thoreson WB. Weak endogenous Ca2+ buffering supports sustained synaptic transmission by distinct mechanisms in rod and cone photoreceptors in salamander retina. Physiol Rep 2015; 3:3/9/e12567. [PMID: 26416977 PMCID: PMC4600400 DOI: 10.14814/phy2.12567] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Differences in synaptic transmission between rod and cone photoreceptors contribute to different response kinetics in rod- versus cone-dominated visual pathways. We examined Ca2+ dynamics in synaptic terminals of tiger salamander photoreceptors under conditions that mimicked endogenous buffering to determine the influence on kinetically and mechanistically distinct components of synaptic transmission. Measurements of ICl(Ca) confirmed that endogenous Ca2+ buffering is equivalent to ˜0.05 mmol/L EGTA in rod and cone terminals. Confocal imaging showed that with such buffering, depolarization stimulated large, spatially unconstrained [Ca2+] increases that spread throughout photoreceptor terminals. We calculated immediately releasable pool (IRP) size and release efficiency in rods by deconvolving excitatory postsynaptic currents and presynaptic Ca2+ currents. Peak efficiency of ˜0.2 vesicles/channel was similar to that of cones (˜0.3 vesicles/channel). Efficiency in both cell types was not significantly affected by using weak endogenous Ca2+ buffering. However, weak Ca2+ buffering speeded Ca2+/calmodulin (CaM)-dependent replenishment of vesicles to ribbons in both rods and cones, thereby enhancing sustained release. In rods, weak Ca2+ buffering also amplified sustained release by enhancing CICR and CICR-stimulated release of vesicles at nonribbon sites. By contrast, elevating [Ca2+] at nonribbon sites in cones with weak Ca2+ buffering and by inhibiting Ca2+ extrusion did not trigger additional release, consistent with the notion that exocytosis from cones occurs exclusively at ribbons. The presence of weak endogenous Ca2+ buffering in rods and cones facilitates slow, sustained exocytosis by enhancing Ca2+/CaM-dependent replenishment of ribbons in both rods and cones and by stimulating nonribbon release triggered by CICR in rods.
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Affiliation(s)
- Matthew J Van Hook
- Truhlsen Eye Institute and Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska
| | - Wallace B Thoreson
- Truhlsen Eye Institute and Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska
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Ophthalmological assessment of cannabis-induced persisting perception disorder: is there a direct retinal effect? Doc Ophthalmol 2015; 130:121-30. [PMID: 25612939 DOI: 10.1007/s10633-015-9481-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/06/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE Cannabis is a psychotomimetic agent that induces impairment of sensory perception. We present detailed clinical and electrophysiological data of patients with hallucinogen persisting perception disorder (HPPD) after marijuana consumption. METHODS A HPPD patient and four heavy cannabis smokers with no visual disturbances (controls) underwent complete ophthalmological examination including psychophysical tests (visual acuity, color vision, visual field, and dark adaptation) and detailed electrophysiological examinations, including extended Ganzfeld ERG, multifocal ERG, and electrooculography (EOG). Furthermore, electrically evoked phosphene thresholds (EPTs) were measured to further evaluate retinal function. RESULTS Ophthalmological and most electrophysiological examinations were within normal limits for the HPPD patient and for all control subjects. Interestingly, EOG results of the HPPD patient showed a slightly reduced fast oscillation ratio, diminished standing potentials of the slow oscillations, and a light peak within normal range resulting in higher Arden ratios. The EPTs of the patient were reduced, in particular for pulses with long durations (50 ms) causing visual sensations even at lowest possible currents of the neurostimulator. The control subjects did not reveal such alterations. CONCLUSIONS Our findings suggest a direct effect of cannabinoids on the retina and retinal pigment epithelium function, which may be involved in disturbances of the visual function experienced after drug consumption. The observations presented here may contribute to the elucidation of the detailed mechanism. Furthermore, EOG and EPT measurements may be useful tools to demonstrate long-term retinal alterations in cannabis-induced HPPD in patients.
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Endocannabinoid CB1 receptor-mediated rises in Ca(2+) and depolarization-induced suppression of inhibition within the laterodorsal tegmental nucleus. Brain Struct Funct 2015; 221:1255-77. [PMID: 25573246 DOI: 10.1007/s00429-014-0969-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 12/12/2014] [Indexed: 12/21/2022]
Abstract
Cannabinoid type 1 receptors (CB1Rs) are functionally active within the laterodorsal tegmental nucleus (LDT), which is critically involved in control of rapid eye movement sleep, cortical arousal, and motivated states. To further characterize the cellular consequences of activation of CB1Rs in this nucleus, we examined whether CB1R activation led to rises in intracellular Ca(2+) ([Ca(2+)]i) and whether processes shown in other regions to involve endocannabinoid (eCB) transmission were present in the LDT. Using a combination of Ca(2+) imaging in multiple cells loaded with Ca(2+) imaging dye via 'bulk-loading' or in single cells loaded with dye via a patch-clamp electrode, we found that WIN 55212-2 (WIN-2), a potent CB1R agonist, induced increases in [Ca(2+)]i which were sensitive to AM251, a CB1R antagonist. A proportion of rises persisted in TTX and/or low-extracellular Ca(2+) conditions. Attenuation of these increases by a reversible inhibitor of sarcoplasmic reticulum Ca(2+)-ATPases, suggests these rises occurred following release of Ca(2+) from intracellular stores. Under voltage clamp conditions, brief, direct depolarization of LDT neurons resulted in a decrease in the frequency and amplitude of AM251-sensitive, inhibitory postsynaptic currents (IPSCs), which was an action sensitive to presence of a Ca(2+) chelator. Finally, actions of DHPG, a mGlu1R agonist, on IPSC activity were examined and found to result in an AM251- and BAPTA-sensitive inhibition of both the frequency and amplitude of sIPSCs. Taken together, our data further characterize CB1R and eCB actions in the LDT and indicate that eCB transmission could play a role in the processes governed by this nucleus.
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Schwitzer T, Schwan R, Angioi-Duprez K, Ingster-Moati I, Lalanne L, Giersch A, Laprevote V. The cannabinoid system and visual processing: a review on experimental findings and clinical presumptions. Eur Neuropsychopharmacol 2015; 25:100-12. [PMID: 25482685 DOI: 10.1016/j.euroneuro.2014.11.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/19/2014] [Accepted: 11/04/2014] [Indexed: 01/27/2023]
Abstract
Cannabis is one of the most prevalent drugs used worldwide. Regular cannabis use is associated with impairments in highly integrative cognitive functions such as memory, attention and executive functions. To date, the cerebral mechanisms of these deficits are still poorly understood. Studying the processing of visual information may offer an innovative and relevant approach to evaluate the cerebral impact of exogenous cannabinoids on the human brain. Furthermore, this knowledge is required to understand the impact of cannabis intake in everyday life, and especially in car drivers. Here we review the role of the endocannabinoids in the functioning of the visual system and the potential involvement of cannabis use in visual dysfunctions. This review describes the presence of the endocannabinoids in the critical stages of visual information processing, and their role in the modulation of visual neurotransmission and visual synaptic plasticity, thereby enabling them to alter the transmission of the visual signal. We also review several induced visual changes, together with experimental dysfunctions reported in cannabis users. In the discussion, we consider these results in relation to the existing literature. We argue for more involvement of public health research in the study of visual function in cannabis users, especially because cannabis use is implicated in driving impairments.
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Affiliation(s)
- Thomas Schwitzer
- EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy F-54000, France; Maison des Addictions, CHU Nancy, Nancy F-54000, France; Centre Psychothérapique de Nancy, Nancy F-54000, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg F-67000, France
| | - Raymund Schwan
- EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy F-54000, France; Maison des Addictions, CHU Nancy, Nancy F-54000, France; Centre d׳Investigation Clinique CIC-INSERM 9501, CHU Nancy, Nancy F-54000, France; Centre Psychothérapique de Nancy, Nancy F-54000, France
| | | | | | - Laurence Lalanne
- Clinique Psychiatrique, CHRU Strasbourg, FTMS, Strasbourg, F-67000, France; INSERM U1114, Physiopathologie et Psychopathologie Cognitive de la Schizophrénie, Hôpitaux Universitaires de Strasbourg, Strasbourg F-67000, France
| | - Anne Giersch
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg F-67000, France
| | - Vincent Laprevote
- EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy F-54000, France; Maison des Addictions, CHU Nancy, Nancy F-54000, France; Centre d׳Investigation Clinique CIC-INSERM 9501, CHU Nancy, Nancy F-54000, France; Centre Psychothérapique de Nancy, Nancy F-54000, France.
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Caldwell MD, Hu SSJ, Viswanathan S, Bradshaw H, Kelly MEM, Straiker A. A GPR18-based signalling system regulates IOP in murine eye. Br J Pharmacol 2014; 169:834-43. [PMID: 23461720 DOI: 10.1111/bph.12136] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 01/17/2013] [Accepted: 02/07/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE GPR18 is a recently deorphaned lipid receptor that is activated by the endogenous lipid N-arachidonoyl glycine (NAGly) as well the behaviourally inactive atypical cannabinoid, abnormal cannabidiol (Abn-CBD). The presence and/or function of any GPR18-based ocular signalling system remain essentially unstudied. The objectives of this research are: (i) to determine the disposition of GPR18 receptors and ligands in anterior murine eye, (ii) examine the effect of GPR18 activation on intraocular pressure (IOP) in a murine model, including knockout mice for CB₁, CB₂ and GPR55. EXPERIMENTAL APPROACH IOP was measured in mice following topical application of Abn-CBD, NAGly or the GPR55/GPR18 agonist O-1602, alone or with injection of the GPR18 antagonist, O-1918. GPR18 protein localization was assessed with immunohistochemistry. Endocannabinoids were measured using LC/MS-MS. KEY RESULTS GPR18 protein was expressed most prominently in the ciliary epithelium and the corneal epithelium and, interestingly, in the trabecular meshwork. The GPR18 ligand, NAGly, was also detected in mouse eye at a level comparable to that seen in the brain. Abn-CBD and NAGly, but not O-1602, significantly reduced IOP in all mice tested. The antagonist, O-1918, blocked the effects of Abn-CBD and NAGly. CONCLUSIONS AND IMPLICATIONS We present evidence for a functional GPR18-based signalling system in the murine anterior eye, including receptors and ligands. GPR18 agonists, Abn-CBD and NAGly, reduce IOP independently of CB₁, CB₂ or GPR55. These findings suggest that GPR18 may serve as a desirable target for the development of novel ocular hypotensive medications.
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Affiliation(s)
- Meggie D Caldwell
- Department of Clinical Vision Science, Dalhousie University, Halifax, NS, Canada
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Wang XH, Wu Y, Yang XF, Miao Y, Zhang CQ, Dong LD, Yang XL, Wang Z. Cannabinoid CB1 receptor signaling dichotomously modulates inhibitory and excitatory synaptic transmission in rat inner retina. Brain Struct Funct 2014; 221:301-16. [DOI: 10.1007/s00429-014-0908-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 09/26/2014] [Indexed: 12/01/2022]
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Ryskamp DA, Redmon S, Jo AO, Križaj D. TRPV1 and Endocannabinoids: Emerging Molecular Signals that Modulate Mammalian Vision. Cells 2014; 3:914-38. [PMID: 25222270 PMCID: PMC4197638 DOI: 10.3390/cells3030914] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/27/2014] [Accepted: 09/05/2014] [Indexed: 01/18/2023] Open
Abstract
Transient Receptor Potential Vanilloid 1 (TRPV1) subunits form a polymodal cation channel responsive to capsaicin, heat, acidity and endogenous metabolites of polyunsaturated fatty acids. While originally reported to serve as a pain and heat detector in the peripheral nervous system, TRPV1 has been implicated in the modulation of blood flow and osmoregulation but also neurotransmission, postsynaptic neuronal excitability and synaptic plasticity within the central nervous system. In addition to its central role in nociception, evidence is accumulating that TRPV1 contributes to stimulus transduction and/or processing in other sensory modalities, including thermosensation, mechanotransduction and vision. For example, TRPV1, in conjunction with intrinsic cannabinoid signaling, might contribute to retinal ganglion cell (RGC) axonal transport and excitability, cytokine release from microglial cells and regulation of retinal vasculature. While excessive TRPV1 activity was proposed to induce RGC excitotoxicity, physiological TRPV1 activity might serve a neuroprotective function within the complex context of retinal endocannabinoid signaling. In this review we evaluate the current evidence for localization and function of TRPV1 channels within the mammalian retina and explore the potential interaction of this intriguing nociceptor with endogenous agonists and modulators.
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Affiliation(s)
- Daniel A Ryskamp
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - Sarah Redmon
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - Andrew O Jo
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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Lax P, Esquiva G, Altavilla C, Cuenca N. Neuroprotective effects of the cannabinoid agonist HU210 on retinal degeneration. Exp Eye Res 2014; 120:175-85. [PMID: 24495949 DOI: 10.1016/j.exer.2014.01.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 11/18/2022]
Abstract
Cannabinoids have been demonstrated to exert neuroprotective effects on different types of neuronal insults. Here we have addressed the therapeutic potential of the synthetic cannabinoid HU210 on photoreceptor degeneration, synaptic connectivity and functional activity of the retina in the transgenic P23H rat, an animal model for autosomal dominant retinitis pigmentosa (RP). In P23H rats administered with HU210 (100 μg/kg, i.p.) from P24 to P90, ERG recordings showed an amelioration of vision loss, as compared to vehicle-administered animals. Under scotopic conditions, the maximum a-wave amplitudes recorded at P60 and P90 were higher in HU210-treated animals, as compared to the values obtained in untreated animals. The scotopic b-waves were significantly higher in treated animals than in untreated rats at P30, P60 and P90. This attenuation of visual deterioration correlated with a delay in photoreceptor degeneration and the preservation of retinal cytoarchitecture. HU210-treated animals had 40% more photoreceptors than untreated animals. Presynaptic and postsynaptic elements, as well as the synaptic contacts between photoreceptors and bipolar or horizontal cells, were also preserved in HU210-treated P23H rats. These results indicate that HU210 preserves cone and rod structure and function, together with their contacts with postsynaptic neurons, in P23H rats. These data suggest that cannabinoids are potentially useful to delay retinal degeneration in RP patients.
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Affiliation(s)
- Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Gema Esquiva
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Cesare Altavilla
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Institute Ramón Margalef, University of Alicante, Alicante, Spain.
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Cécyre B, Thomas S, Ptito M, Casanova C, Bouchard JF. Evaluation of the specificity of antibodies raised against cannabinoid receptor type 2 in the mouse retina. Naunyn Schmiedebergs Arch Pharmacol 2013; 387:175-84. [DOI: 10.1007/s00210-013-0930-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 10/14/2013] [Indexed: 12/11/2022]
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Zhang CQ, Wu HJ, Wang SY, Yin S, Lu XJ, Miao Y, Wang XH, Yang XL, Wang Z. Suppression of outward K⁺ currents by WIN55212-2 in rat retinal ganglion cells is independent of CB1/CB2 receptors. Neuroscience 2013; 253:183-93. [PMID: 24013008 DOI: 10.1016/j.neuroscience.2013.08.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 08/25/2013] [Accepted: 08/26/2013] [Indexed: 10/26/2022]
Abstract
Cannabinoid CB1 receptor (CB1R) signaling system is extensively distributed in the vertebrate retina. Activation of CB1Rs regulates a variety of functions of retinal neurons through modulating different ion channels. In the present work we studied effects of this receptor signaling on K(+) channels in retinal ganglion cells by patch-clamp techniques. The CB1R agonist WIN55212-2 (WIN) suppressed outward K(+) currents in acutely isolated rat retinal ganglion cells in a dose-dependent manner, with an IC50 of 4.7 μM. We further showed that WIN mainly suppressed the tetraethylammonium (TEA)-sensitive K(+) current component. While CB1Rs were expressed in rat retinal ganglion cells, the WIN effect on K(+) currents was not blocked by either AM251/SR141716, specific CB1R antagonists, or AM630, a selective CB2R antagonist. Consistently, cAMP-protein kinase A (PKA) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathways were unlikely involved in the WIN-induced suppression of the K(+) currents because both PKA inhibitors H-89/Rp-cAMP and MAPK/ERK1/2 inhibitor U0126 failed to block the WIN effects. WIN-induced suppression of the K(+) currents was not observed when WIN was intracellularly applied. Furthermore, an endogenous ligand of the cannabinoid receptor anandamide, the specific CB1R agonist ACEA and the selective CB2R agonist CB65 also suppressed the K(+) currents, and the effects were not blocked by AM251/SR141716 or AM630 respectively. All these results suggest that the WIN-induced suppression of the outward K(+) currents in rat retinal ganglion cells, thereby regulating the cell excitability, were not through CB1R/CB2R signaling pathways.
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Affiliation(s)
- C-Q Zhang
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
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Liu X, Hirano AA, Sun X, Brecha NC, Barnes S. Calcium channels in rat horizontal cells regulate feedback inhibition of photoreceptors through an unconventional GABA- and pH-sensitive mechanism. J Physiol 2013; 591:3309-24. [PMID: 23613534 DOI: 10.1113/jphysiol.2012.248179] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Horizontal cells send inhibitory feedback to photoreceptors, helping form antagonistic receptive fields in the retina, but the neurotransmitter and the mechanisms underlying this signalling are not known. Since the proteins responsible for conventional Ca(2+)-dependent release of GABAergic synaptic vesicles are present in mammalian horizontal cells, we investigated this conventional mechanism as the means by which horizontal cells inhibit photoreceptors. Using Ca(2+) imaging in rat retinal slices, we confirm that horizontal cell depolarization with kainate inhibits and horizontal cell hyperpolarization with NBQX disinhibits the Ca(2+) signals produced by pH-sensitive activation of voltage-gated calcium channels (Ca channels) in photoreceptors. We show that while 100 μm Co(2+) reduces photoreceptor Ca(2+) signals, it disinhibits them at 10 μm, an effect reminiscent of earlier studies where low [Co(2+)] eliminated feedback. The low [Co(2+)] disinhibition is pH sensitive. We localized L-, N- and P/Q-type Ca channels in rat horizontal cells, and showed that both the N-type Ca channel blocker -conotoxin GVIA and the P/Q-type Ca channel blocker -agatoxin IVA increased Ca(2+) signals in photoreceptors in a pH-sensitive manner. Pronounced actions of GABAergic agents on feedback signals to photoreceptors were observed, and are pH sensitive, but are inconsistent with direct inhibition by GABA of photoreceptor [Ca(2+)]. Patch-clamp studies revealed that GABA activates a conductance having high bicarbonate permeability in isolated horizontal cells, suggesting that the commonality of pH sensitivity throughout the results could arise from a GABA autofeedback action in horizontal cells. This could change cleft pH with concomitant inhibitory influences on photoreceptor Ca channels.
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Affiliation(s)
- Xue Liu
- S. Barnes: Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Krishnan G, Chatterjee N. Endocannabinoids alleviate proinflammatory conditions by modulating innate immune response in muller glia during inflammation. Glia 2012; 60:1629-45. [DOI: 10.1002/glia.22380] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/05/2012] [Indexed: 12/29/2022]
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Abstract
The endocannabinoid (ECB) system has been found throughout the central nervous system and modulates cell excitability in various forms of short-term plasticity. ECBs and their receptors have also been localized to all retinal cells, and cannabinoid receptor activation has been shown to alter voltage-dependent conductances in several different retinal cell types, suggesting a possible role for cannabinoids in retinal processing. Their effects on synaptic transmission in the mammalian retina, however, have not been previously investigated. Here, we show that exogenous cannabinoids alter spontaneous synaptic transmission onto retinal ganglion cells (RGCs). Using whole-cell voltage-clamp recordings in whole-mount retinas, we measured spontaneous postsynaptic currents (SPSCs) in RGCs in adult and young (P14-P21) mice. We found that the addition of an exogenous cannabinoid agonist, WIN55212-2 (5 μM), caused a significant reversible reduction in the frequency of SPSCs. This change, however, did not alter the kinetics of the SPSCs, indicating a presynaptic locus of action. Using blockers to isolate inhibitory or excitatory currents, we found that cannabinoids significantly reduced the release probability of both GABA and glutamate, respectively. While the addition of cannabinoids reduced the frequency of both GABAergic and glutamatergic SPSCs in both young and adult mice, we found that the largest effect was on GABA-mediated currents in young mice. These results suggest that the ECB system may potentially be involved in the modulation of signal transmission in the retina. Furthermore, they suggest that it might play a role in the developmental maturation of synaptic circuits, and that exogenous cannabinoids are likely able to disrupt retinal processing and consequently alter vision.
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Zabouri N, Bouchard JF, Casanova C. Cannabinoid receptor type 1 expression during postnatal development of the rat retina. J Comp Neurol 2011; 519:1258-80. [DOI: 10.1002/cne.22534] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Hu SSJ, Arnold A, Hutchens JM, Radicke J, Cravatt BF, Wager-Miller J, Mackie K, Straiker A. Architecture of cannabinoid signaling in mouse retina. J Comp Neurol 2010; 518:3848-66. [PMID: 20653038 DOI: 10.1002/cne.22429] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cannabinoid receptors and their ligands constitute an endogenous signaling system that is found throughout the body, including the eye. This system can be activated by Delta(9)-tetrahydrocannabinol, a major drug of abuse. Cannabinoids offer considerable therapeutic potential in modulating ocular immune and inflammatory responses and in regulating intraocular pressure. The location of cannabinoid receptor 1 (CB(1)) in the retina is known, but recently a constellation of proteins has been identified that produce and break down endocannabinoids (eCBs) and modulate CB(1) function. Localization of these proteins is critical to defining specific cannabinoid signaling circuitry in the retina. Here we show the localization of diacylglycerol lipase-alpha and -beta (DGLalpha/beta), implicated in the production of the eCB 2-arachidonoyl glycerol (2-AG); monoacylglycerol lipase (MGL) and alpha/beta-hydrolase domain 6 (ABHD6), both implicated in the breakdown of 2-AG; cannabinoid receptor-interacting protein 1a (CRIP1a), a protein that may modulate CB(1) function; and fatty acid amide hydrolase (FAAH) and N-acylethanolamine-hydrolyzing acid amidase (NAAA), which have been shown to break down the eCB anandamide and related acyl amides. Our most prominent finding was that DGLalpha is present in postsynaptic type 1 OFF cone bipolar cells juxtaposed to CB(1)-containing cone photoreceptor terminals. CRIP1a is reliably presynaptic to DGLalpha, consistent with a possible role in cannabinoid signaling, and NAAA is restricted to retinal pigment epithelium, whereas DGLbeta is limited to retinal blood vessels. These results taken together with previous anatomical and functional studies define specific cannabinoid circuitry likely to modulate eCB signaling at the first synapse of the retina as well as in the inner plexiform layer.
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Affiliation(s)
- Sherry Shu-Jung Hu
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405, USA
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Leonelli M, Martins DO, Kihara AH, Britto LRG. Ontogenetic expression of the vanilloid receptors TRPV1 and TRPV2 in the rat retina. Int J Dev Neurosci 2009; 27:709-18. [PMID: 19619635 DOI: 10.1016/j.ijdevneu.2009.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/06/2009] [Accepted: 07/11/2009] [Indexed: 01/13/2023] Open
Abstract
The present study aimed to analyze the gene and protein expression and the pattern of distribution of the vanilloid receptors TRPV1 and TRPV2 in the developing rat retina. During the early phases of development, TRPV1 was found mainly in the neuroblastic layer of the retina and in the pigmented epithelium. In the adult, TRPV1 was found in microglial cells, blood vessels, astrocytes and in neuronal structures, namely synaptic boutons of both retinal plexiform layers, as well as in cell bodies of the inner nuclear layer and the ganglion cell layer. The pattern of distribution of TRPV1 was mainly punctate, and there was higher TRPV1 labeling in the peripheral retina than in central regions. TRPV2 expression was quite distinct. Its expression was virtually undetectable by immunoblotting before P1, and that receptor was found by immunohistochemistry only by postnatal day 15 (P15). RNA and protein analysis showed that the adult levels are only reached by P60, which includes small processes in the retinal plexiform layers, and labeled cellular bodies in the inner nuclear layer and the ganglion cell layer. There was no overlapping between the signal observed for both receptors. In conclusion, our results showed that the patterns of distribution of TRPV1 and TRPV2 are different during the development of the rat retina, suggesting that they have specific roles in both visual processing and in providing specific cues to neural development.
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Affiliation(s)
- Mauro Leonelli
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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Elphick MR, Egertová M. Cannabinoid Receptor Genetics and Evolution. THE CANNABINOID RECEPTORS 2009. [DOI: 10.1007/978-1-59745-503-9_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Abstract
The active component of the marijuana plant Cannabis sativa, Delta9-tetrahydrocannabinol (THC), produces numerous beneficial effects, including analgesia, appetite stimulation and nausea reduction, in addition to its psychotropic effects. THC mimics the action of endogenous fatty acid derivatives, referred to as endocannabinoids. The effects of THC and the endocannabinoids are mediated largely by metabotropic receptors that are distributed throughout the nervous and peripheral organ systems. There is great interest in endocannabinoids for their role in neuroplasticity as well as for therapeutic use in numerous conditions, including pain, stroke, cancer, obesity, osteoporosis, fertility, neurodegenerative diseases, multiple sclerosis, glaucoma and inflammatory diseases, among others. However, there has been relatively far less research on this topic in the eye and retina compared with the brain and other organ systems. The purpose of this review is to introduce the "cannabinergic" field to the retinal community. All of the fundamental works on cannabinoids have been performed in non-retinal preparations, necessitating extensive dependence on this literature for background. Happily, the retinal cannabinoid system has much in common with other regions of the central nervous system. For example, there is general agreement that cannabinoids suppress dopamine release and presynaptically reduce transmitter release from cones and bipolar cells. How these effects relate to light and dark adaptations, receptive field formation, temporal properties of ganglion cells or visual perception are unknown. The presence of multiple endocannabinoids, degradative enzymes with their bioactive metabolites, and receptors provides a broad spectrum of opportunities for basic research and to identify targets for therapeutic application to retinal diseases.
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Affiliation(s)
- Stephen Yazulla
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794-5230, United States.
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Thoreson WB. Kinetics of synaptic transmission at ribbon synapses of rods and cones. Mol Neurobiol 2007; 36:205-23. [PMID: 17955196 PMCID: PMC2474471 DOI: 10.1007/s12035-007-0019-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 05/18/2007] [Indexed: 11/24/2022]
Abstract
The ribbon synapse is a specialized structure that allows photoreceptors to sustain the continuous release of vesicles for hours upon hours and years upon years but also respond rapidly to momentary changes in illumination. Light responses of cones are faster than those of rods and, mirroring this difference, synaptic transmission from cones is also faster than transmission from rods. This review evaluates the various factors that regulate synaptic kinetics and contribute to kinetic differences between rod and cone synapses. Presynaptically, the release of glutamate-laden synaptic vesicles is regulated by properties of the synaptic proteins involved in exocytosis, influx of calcium through calcium channels, calcium release from intracellular stores, diffusion of calcium to the release site, calcium buffering, and extrusion of calcium from the cytoplasm. The rate of vesicle replenishment also limits the ability of the synapse to follow changes in release. Post-synaptic factors include properties of glutamate receptors, dynamics of glutamate diffusion through the cleft, and glutamate uptake by glutamate transporters. Thus, multiple synaptic mechanisms help to shape the responses of second-order horizontal and bipolar cells.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, 4th floor, Durham Research Center, 985840 Nebraska Medical Center, Omaha, NE 68198-5840, USA.
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Warrier A, Wilson M. Endocannabinoid signaling regulates spontaneous transmitter release from embryonic retinal amacrine cells. Vis Neurosci 2007; 24:25-35. [PMID: 17430607 DOI: 10.1017/s0952523807230160] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 07/06/2006] [Indexed: 11/07/2022]
Abstract
GABAergic amacrine cells, cultured from embryonic chick retina, display spontaneous mini frequencies ranging from 0-4.6 Hz as a result of the release of quanta of transmitter from both synapses and autapses. We show here that at least part of this variation originates from differences in the degree to which endocannabinoids, endogenously generated within the culture, are present at terminals presynaptic to individual cells. Though all cells examined scored positive for cannabinoid receptor type I (CB1R), only those showing a low initial rate of spontaneous minis responded to CB1R agonists with an increase in mini frequency, caused by a Gi/o-mediated reduction in [cAMP]. Cells displaying a high initial rate of spontaneous minis, on the other hand, were unaffected by CB1R agonists, but they did show a rate decrease with CB1R antagonists. Such a regulation of spontaneous transmitter release by endocannabinoids might be important in network maintenance in amacrine cells and other inhibitory interneurons.
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Affiliation(s)
- Ajithkumar Warrier
- Section of Neurobiology, Physiology and Behavior, Division of Biological Sciences, Davis, California 95616, USA
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Fan SF, Yazulla S. Retrograde endocannabinoid inhibition of goldfish retinal cones is mediated by 2-arachidonoyl glycerol. Vis Neurosci 2007; 24:257-67. [PMID: 17592669 DOI: 10.1017/s095252380707006x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 01/19/2007] [Indexed: 11/07/2022]
Abstract
A functional role for retinal endocannabinoids has not been determined. We characterized retrograde suppression of membrane currents of goldfish cones in a retinal slice. Whole-cell recordings were obtained from cone inner segments under voltage clamp. I(K(V)) was elicited by a depolarizing pulse to +54 mV from a holding potential of -70 mV. A fifty-millisecond puff of saline with 70 mM KCl or Group I mGluR agonist DHPG was applied through a pipette directly at a mixed rod/cone (Mb) bipolar cell body. The amplitude of I(K(V)) decreased 25% compared to the pre-puff control. Retrograde suppression of I(K(V)) was blocked by CB1 receptor antagonist, SR141716A. The FAAH inhibitor URB597 had no effect on the suppression of I(K(V)), whereas nimesulide, a COX-2 inhibitor, prolonged the effects of the K+ puff 10-fold. Orlistat, a blocker of 2-AG synthesis, blocked the effect of the K+ puff. Group I mGluR activation of Gq/11 was demonstrated in that a puff with DHPG decreased I(K(V)) of cones by 32%, an effect blocked by SR141716A. The effect of DHPG was not blocked by the mGluR5 antagonist MPEP, indicating involvement of mGluR1. The suppressive effect of the K+ puff vanished in a Ca2+-free, 2 mM Co2+ saline. TMB-8 or ryanodine, blocked the effect of DHPG, but not that of the K+ puff, showing that calcium influx or release from intracellular stores could mediate retrograde release. We suggest that retrograde suppression of cone I(K(V)) is mediated by Ca2+-dependent release of 2-AG from Mb bipolar cell dendrites by separate mechanisms: (1) voltage-dependent, mimicked by the K+ puff, that may be activated by the depolarizing ON response to light; (2) voltage-independent, occurring under ambient illumination, mediated by tonic mGluR1 activation. The negative feedback of this latter mechanism could regulate tonic glutamate release from cones within narrow limits, regardless of ambient illumination.
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Affiliation(s)
- Shih-Fang Fan
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794-5230, USA
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Czesnik D, Schild D, Kuduz J, Manzini I. Cannabinoid action in the olfactory epithelium. Proc Natl Acad Sci U S A 2007; 104:2967-72. [PMID: 17301239 PMCID: PMC1815290 DOI: 10.1073/pnas.0609067104] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Indexed: 11/18/2022] Open
Abstract
The perception of odors is influenced by a variety of neuromodulators, and there is growing evidence that modulation already takes place in the olfactory epithelium. Here we report on cannabinergic actions in the olfactory epithelium of Xenopus laevis tadpoles. First we show that CB1 receptor-specific antagonists AM251, AM281, and LY320135 modulate odor-evoked calcium changes in olfactory receptor neurons. Second, we localize CB1-like immunoreactivity on dendrites of olfactory receptor neurons. Finally, we describe the cannabinergic influence on odor-induced spike-associated currents in individual olfactory receptor neurons. Here we demonstrate that the cannabinergic system has a profound impact on peripheral odor processing and discuss its possible function.
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Affiliation(s)
- Dirk Czesnik
- Department of Neurophysiology and Cellular Biophysics and Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
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Matias I, Wang JW, Moriello AS, Nieves A, Woodward DF, Di Marzo V. Changes in endocannabinoid and palmitoylethanolamide levels in eye tissues of patients with diabetic retinopathy and age-related macular degeneration. Prostaglandins Leukot Essent Fatty Acids 2006; 75:413-8. [PMID: 17011761 DOI: 10.1016/j.plefa.2006.08.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 08/07/2006] [Indexed: 01/15/2023]
Abstract
Cannabinoid receptors and the endocannabinoids (anandamide (N-arachidonoylethanolamine--AEA) and 2-arachidonoylglycerol (2-AG)), as well as the AEA congener, palmitoylethanolamide (PEA), are involved in ocular physiology. We measured endocannabinoid and PEA levels by isotope-dilution liquid chromatography-mass spectrometric analysis in post-mortem eye tissues of patients with diabetic retinopathy (DR) or age-related macular degeneration (AMD). In eyes with DR, significantly enhanced levels of AEA were found in the retina ( approximately 1.8-fold), ciliary body ( approximately 1.5-fold) and, to a lesser extent, cornea ( approximately 1.3-fold). Surprisingly, 2-AG levels were significantly higher ( approximately 3-fold) only in the iris, whereas PEA levels only slightly increased ( approximately 1.3-fold) in the ciliary body. In eyes with AMD, significantly enhanced levels of AEA were found in the choroid ( approximately 1.3-fold), ciliary body ( approximately 1.4-fold) and cornea ( approximately 1.4-fold), whereas in the retina only a trend towards an increase ( approximately 1.5-fold) was observed. The tissue- and disease-selective nature of the changes observed suggests that the compounds analyzed here may play different roles in the control of eye function under different pathological conditions.
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Affiliation(s)
- I Matias
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Toiano 6, 80072 Arco Felice, Pozzuoli (Napoli), Italy
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Struik ML, Yazulla S, Kamermans M. Cannabinoid agonist WIN 55212-2 speeds up the cone response to light offset in goldfish retina. Vis Neurosci 2006; 23:285-93. [PMID: 16638179 DOI: 10.1017/s0952523806232127] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 01/03/2006] [Indexed: 11/05/2022]
Abstract
Goldfish cones contain CB1 receptors at the synaptic terminal, selectively accumulate3H-anandamide, and contain fatty acid amide hydrolase-immunoreactivity, and voltage-gated calcium and potassium currents are modulated by CB1 ligands (Yazulla et al., 2000; Fan & Yazulla, 2003; Glaser et al., 2005). These data suggest that a retinal mechanism may account for some of the psychophysical effects of cannabis. Here, we studied the effect of a cannabinoid agonist on cone light responses. Whole-cell patch-clamp recordings were made from cones in the isolated goldfish retina. Cones were stimulated with a spot of light of variable wavelength and intensities in combination with voltage-and current-clamp protocols. Pharmacological manipulation was performed using the cannabinoid agonist WIN 55212-2 (10 μM). WIN had no effect on the absolute sensitivity of the cones or on the kinetics of the onset response. However, the light-offset response became faster, and the depolarizing overshoot was enhanced. Time constant of the offset response was reduced from 292 ± 28 ms to 180 ± 11 ms (n= 6) (P< 0.01) in the presence of WIN. Acceleration of the offset response was not affected by flash length from 200 ms to 10 s. This was found under current-clamp as well as under voltage-clamp conditions, indicating that the effect of WIN was mediated directly or indirectly by modulation of the cGMP-gated channels in the outer segment of the cones. The effects of WIN were not blocked by the CB1 antagonist SR141716A. With a train of “dark” flashes from a steady background, the photocurrent recovered toward baseline more quickly with WIN than in Control. In summary, cannabinoids speed up the dynamics of the phototransduction deactivation cascade in the cone outer segments. The functional consequence of this effect is to shorten the recovery time to the offset of bright flashes, perhaps resulting in an increase in contrast sensitivity.
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Affiliation(s)
- Mieke L Struik
- The Netherlands Ophthalmic Research Institute, Amsterdam, The Netherlands
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Hosoi N, Arai I, Tachibana M. Group III metabotropic glutamate receptors and exocytosed protons inhibit L-type calcium currents in cones but not in rods. J Neurosci 2006; 25:4062-72. [PMID: 15843608 PMCID: PMC6724956 DOI: 10.1523/jneurosci.2735-04.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Light responses of photoreceptors (rods and cones) are transmitted to the second-order neurons (bipolar cells and horizontal cells) via glutamatergic synapses located in the outer plexiform layer of the retina. Although it has been well established that postsynaptic group III metabotropic glutamate receptors (mGluRs) of ON bipolar cells contribute to generating the ON signal, presynaptic roles of group III mGluRs remain to be elucidated at this synaptic connection. We addressed this issue by applying the slice patch-clamp technique to the newt retina. OFF bipolar cells and horizontal cells generate a steady inward current in the dark and a transient inward current at light offset, both of which are mediated via postsynaptic non-NMDA receptors. A group III mGluR-specific agonist, L-2-amino-4-phosphonobutyric acid (L-AP-4), inhibited both the steady and off-transient inward currents but did not affect the glutamate-induced current in these postsynaptic neurons. L-AP-4 inhibited the presynaptic L-type calcium current (ICa) in cones by shifting the voltage dependence of activation to more positive membrane potentials. The inhibition of ICa was most prominent around the physiological range of cone membrane potentials. In contrast, L-AP-4 did not affect L-type ICa in rods. Paired recordings from photoreceptors and the synaptically connected second-order neurons confirmed that L-AP-4 inhibited both ICa and glutamate release in cones but not in rods. Furthermore, we found that exocytosed protons also inhibited ICa in cones but not in rods. Selective modulation of ICa in cones may help broaden the dynamic range of synaptic transfer by controlling the amount of transmitter release from cones.
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Affiliation(s)
- Nobutake Hosoi
- Department of Psychology, Graduate School of Humanities and Sociology, The University of Tokyo, Tokyo 113-0033, Japan
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