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Voicu V, Brehar FM, Toader C, Covache-Busuioc RA, Corlatescu AD, Bordeianu A, Costin HP, Bratu BG, Glavan LA, Ciurea AV. Cannabinoids in Medicine: A Multifaceted Exploration of Types, Therapeutic Applications, and Emerging Opportunities in Neurodegenerative Diseases and Cancer Therapy. Biomolecules 2023; 13:1388. [PMID: 37759788 PMCID: PMC10526757 DOI: 10.3390/biom13091388] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/08/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
In this review article, we embark on a thorough exploration of cannabinoids, compounds that have garnered considerable attention for their potential therapeutic applications. Initially, this article delves into the fundamental background of cannabinoids, emphasizing the role of endogenous cannabinoids in the human body and outlining their significance in studying neurodegenerative diseases and cancer. Building on this foundation, this article categorizes cannabinoids into three main types: phytocannabinoids (plant-derived cannabinoids), endocannabinoids (naturally occurring in the body), and synthetic cannabinoids (laboratory-produced cannabinoids). The intricate mechanisms through which these compounds interact with cannabinoid receptors and signaling pathways are elucidated. A comprehensive overview of cannabinoid pharmacology follows, highlighting their absorption, distribution, metabolism, and excretion, as well as their pharmacokinetic and pharmacodynamic properties. Special emphasis is placed on the role of cannabinoids in neurodegenerative diseases, showcasing their potential benefits in conditions such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. The potential antitumor properties of cannabinoids are also investigated, exploring their potential therapeutic applications in cancer treatment and the mechanisms underlying their anticancer effects. Clinical aspects are thoroughly discussed, from the viability of cannabinoids as therapeutic agents to current clinical trials, safety considerations, and the adverse effects observed. This review culminates in a discussion of promising future research avenues and the broader implications for cannabinoid-based therapies, concluding with a reflection on the immense potential of cannabinoids in modern medicine.
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Affiliation(s)
- Victor Voicu
- Pharmacology, Toxicology and Clinical Psychopharmacology, “Carol Davila” University of Medicine and Pharmacy in Bucharest, 020021 Bucharest, Romania;
- Medical Section within the Romanian Academy, 010071 Bucharest, Romania
| | - Felix-Mircea Brehar
- Neurosurgery Department, Emergency Clinical Hospital Bagdasar-Arseni, 041915 Bucharest, Romania
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Corneliu Toader
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
- Department of Vascular Neurosurgery, National Institute of Neurology and Neurovascular Diseases, 077160 Bucharest, Romania
| | - Razvan-Adrian Covache-Busuioc
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Antonio Daniel Corlatescu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Andrei Bordeianu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Horia Petre Costin
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Bogdan-Gabriel Bratu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Luca-Andrei Glavan
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
| | - Alexandru Vlad Ciurea
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (R.-A.C.-B.); (A.D.C.); (A.B.); (H.P.C.); (B.-G.B.); (L.-A.G.); (A.V.C.)
- Neurosurgery Department, Sanador Clinical Hospital, 010991 Bucharest, Romania
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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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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: 5] [Impact Index Per Article: 1.7] [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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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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Deák F, Anderson RE, Fessler JL, Sherry DM. Novel Cellular Functions of Very Long Chain-Fatty Acids: Insight From ELOVL4 Mutations. Front Cell Neurosci 2019; 13:428. [PMID: 31616255 PMCID: PMC6763723 DOI: 10.3389/fncel.2019.00428] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 09/06/2019] [Indexed: 12/22/2022] Open
Abstract
Elongation of Very Long chain fatty acids-4 (ELOVL4) protein is a member of the ELOVL family of fatty acid elongases that is collectively responsible for catalyzing formation of long chain fatty acids. ELOVL4 is the only family member that catalyzes production of Very Long Chain Saturated Fatty Acids (VLC-SFA) and Very Long Chain Polyunsaturated Fatty Acids (VLC-PUFA) with chain lengths ≥28 carbons. ELOVL4 and its VLC-SFA and VLC-PUFA products are emerging as important regulators of synaptic signaling and neuronal survival in the central nervous system (CNS). Distinct sets of mutations in ELOVL4 cause three different neurological diseases in humans. Heterozygous inheritance of one set of autosomal dominant ELOVL4 mutations that leads to truncation of the ELOVL4 protein causes Stargardt-like macular dystrophy (STGD3), an aggressive juvenile-onset retinal degeneration. Heterozygous inheritance of a different set of autosomal dominant ELOVL4 mutations that leads to a full-length protein with single amino acid substitutions causes spinocerebellar ataxia 34 (SCA34), a late-onset neurodegenerative disease characterized by gait ataxia and cerebellar atrophy. Homozygous inheritance of a different set of ELOVL4 mutations causes a more severe disease with infantile onset characterized by seizures, spasticity, intellectual disability, ichthyosis, and premature death. ELOVL4 is expressed widely in the CNS and is found primarily in neurons. ELOVL4 is expressed in cell-specific patterns within different regions of the CNS that are likely to be related to disease symptoms. In the retina, ELOVL4 is expressed exclusively in photoreceptors and produces VLC-PUFA that are incorporated into phosphatidylcholine and enriched in the light sensitive membrane disks of the photoreceptor outer segments. VLC-PUFA are enzymatically converted into "elovanoid" compounds that appear to provide paracrine signals that promote photoreceptor and neuronal survival. In the brain, the main ELOVL4 products are VLC-SFA that are incorporated into sphingolipids and enriched in synaptic vesicles, where they regulate kinetics of presynaptic neurotransmitter release. Understanding the function of ELOVL4 and its VLC-SFA and VLC-PUFA products will advance our understanding of basic mechanisms in neural signaling and has potential for developing novel therapies for seizure and neurodegenerative diseases.
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Affiliation(s)
- Ferenc Deák
- Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Robert E Anderson
- Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jennifer L Fessler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - David M Sherry
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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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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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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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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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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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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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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12
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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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13
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Orisme W, Li J, Goldmann T, Bolch S, Wolfrum U, Smith WC. Light-dependent translocation of arrestin in rod photoreceptors is signaled through a phospholipase C cascade and requires ATP. Cell Signal 2010; 22:447-56. [PMID: 19887106 DOI: 10.1016/j.cellsig.2009.10.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 10/26/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
Partitioning of cellular components is a critical mechanism by which cells can regulate their activity. In rod photoreceptors, light induces a large-scale translocation of arrestin from the inner segments to the outer segments. The purpose of this project is to elucidate the signaling pathway necessary to initiate arrestin translocation to the outer segments and the mechanism for arrestin translocation. Mouse retinal organotypic cultures and eyes from transgenic Xenopus tadpoles expressing a fusion of GFP and rod arrestin were treated with both activators and inhibitors of proteins in the phosphoinositide pathway. Confocal microscopy was used to image the effects of the pharmacological agents on arrestin translocation in rod photoreceptors. Retinas were also depleted of ATP using potassium cyanide to assess the requirement for ATP in arrestin translocation. In this study, we demonstrate that components of the G-protein-linked phospholipase C (PLC) pathway play a role in initiating arrestin translocation. Our results show that arrestin translocation can be stimulated by activators of PLC and protein kinase C (PKC), and by cholera toxin in the absence of light. Arrestin translocation to the outer segments is significantly reduced by inhibitors of PLC and PKC. Importantly, we find that treatment with potassium cyanide inhibits arrestin translocation in response to light. Collectively, our results suggest that arrestin translocation is initiated by a G-protein-coupled cascade through PLC and PKC signaling. Furthermore, our results demonstrate that at least the initiation of arrestin translocation requires energy input.
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Affiliation(s)
- Wilda Orisme
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610-0284, USA
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14
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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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15
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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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16
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Zimov S, Yazulla S. Vanilloid receptor 1 (TRPV1/VR1) co-localizes with fatty acid amide hydrolase (FAAH) in retinal amacrine cells. Vis Neurosci 2007; 24:581-91. [PMID: 17686199 DOI: 10.1017/s095252380707054x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Accepted: 05/23/2007] [Indexed: 11/06/2022]
Abstract
Fatty acid amide hydrolase (FAAH) is the degradative enzyme for anandamide (AEA), an endogenous ligand for the vanilloid receptor (TRPV1) and cannabinoid receptor 1. As FAAH and TRPV1 are integral membrane proteins, FAAH activity could modulate the availability of AEA for TRPV1 activation. Previous studies in this laboratory reported an extensive endocannabinoid system in goldfish retina. Immunocytochemistry was used to determine the relative distributions of FAAH-immunoreactivity (IR) and TRPV1-IR in goldfish retina. Here, we show the first example in an intact neural system in which TRPV1-IR co-localizes in subpopulations of FAAH-immunoreactive neurons, in this case amacrine cells. These cells are rare and consist of three subtypes: 1. ovoid cell with granular-type dendrites restricted to sublamina a, 2. pyriform cell with smooth processes in sublamina b, and 3. fusiform cell with smooth processes that project to sublaminae a and b. The varied appearances of reaction product in the dendrites suggest different subcellular localization of TRPV1, and hence function of FAAH activity regarding TRPV1 stimulation among the cell types. Ovoid and pyriform amacrine cells, but not fusiform cells, labeled with GAD-IR and constituted subsets of GABAergic amacrine cells. TRPV1 amacrine cells, though rare, are represented in the ON, OFF and ON/OFF pathways of the retina. As TRPV1 stimulation increases intracellular calcium with numerous downstream effects, co-localization of TRPV1 and FAAH suggests an autoregulatory function for anandamide. Due to the rarity of these cells, the three vanilloid amacrine cell types may be involved in global effects rather than feature extraction, for example: sampling of ambient light or maintaining homeostasis.
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Affiliation(s)
- Sarah Zimov
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York 11794, USA
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17
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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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18
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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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19
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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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20
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Vásquez C, Navarro-Polanco R, Hernández G, Ruiz J, Guerra DG, Baltazar LM, Huerta M, Trujillo X. Cannabinoids and dopamine receptors' action on calcium current in rat neurons. Can J Neurol Sci 2006; 32:529-37. [PMID: 16408587 DOI: 10.1017/s031716710000456x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To study the effects of cannabinoid, glutamate, and dopamine agonists and antagonists on the calcium current rat sympathetic neurons. METHODS Calcium current was recorded using the whole-cell variant of the patch-clamp technique. After expression in neuronal membranes of the cannabinoid CB1, glutamate mGluR2, or dopamine D1 receptor (by microinjection of the levant receptor's cDNA into the neuron's nucleus) agonists' and antagonists' effects were observed. RESULTS Applications of agonists of the expressed receptor (0.1-10 microM) decreased the calcium current. The calcium current was increased after application of cannabinoid antagonists (AM251 and AM630); these compounds thus act as inverse agonists in this preparation. Glutamate and dopamine antagonists had no effects on the calcium current by themselves. Combined application of cannabinoids and dopamine, but not glutamate, agonists produced a decrement in the calcium current that was bigger than either of the effects seen when one agonist was applied alone. CONCLUSIONS These results suggest that cannabinoid with dopamine receptors have an interactive inhibitory effect on the calcium current in this preparation, indicating that within the nervous system, receptor interactions may be important in the regulation of ion-channel functions.
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MESH Headings
- Animals
- Calcium/metabolism
- Male
- Neurons/cytology
- Neurons/metabolism
- Patch-Clamp Techniques
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/metabolism
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/antagonists & inhibitors
- Receptors, Metabotropic Glutamate/metabolism
- Superior Cervical Ganglion/cytology
- Superior Cervical Ganglion/metabolism
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Affiliation(s)
- C Vásquez
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colonia Villa de San Sebastián, Colima, CP, Mexico
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21
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Glaser ST, Deutsch DG, Studholme KM, Zimov S, Yazulla S. Endocannabinoids in the intact retina: 3H-anandamide
uptake, fatty acid amide hydrolase immunoreactivity and hydrolysis of
anandamide. Vis Neurosci 2006; 22:693-705. [PMID: 16469181 DOI: 10.1017/s0952523805226020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Accepted: 04/12/2005] [Indexed: 11/05/2022]
Abstract
There is much evidence for an endocannabinoid system in the retina.
However, neither the distribution of endocannabinoid uptake, the
regulation of endocannabinoid levels, nor the role of endocannabinoid
metabolism have been investigated in the retina. Here we focused on one
endocannabinoid, anandamide (AEA), and its major hydrolyzing enzyme, fatty
acid amide hydrolase (FAAH), in the goldfish retina. Immunoblots of FAAH
immunoreactivity (IR) in goldfish retina, brain and rat retina, and brain
homogenates showed a single band at 61 kDa that was blocked by
preadsorption with peptide antigen. Specific FAAH IR (blocked by
preadsorption) was most prominent over Müller cells and cone inner
segments. Weaker label was observed over some amacrine cells, rare cell
bodies in the ganglion cell layer, and in four lamina in the inner
plexiform layer. FAAH activity assays showed that goldfish-retinal and
brain homogenates hydrolyzed AEA at rates comparable to rat brain
homogenate, and the hydrolysis was inhibited by methyl arachidonyl
fluorophosphonate (MAFP) and N-(4 hydroxyphenyl)-arachidonamide
(AM404), with IC50s of 21 nM and 1.5 μM,
respectively. Cellular 3H-AEA uptake in the intact retina was
determined by in vitro autoradiography. Silver-grain accumulation
at 20°C was most prominent over cone photoreceptors and Müller
cells. Uptake was significantly reduced when retinas were incubated at
4°C, or preincubated with 100 nM MAFP or 10 μM AM404. There was no
differential effect of blocking conditions on the distribution of silver
grains over cones or Müller cells. The codistribution of FAAH IR and
3H-AEA uptake in cones and Müller cells suggests that the
bulk clearance of AEA in the retina occurs as a consequence of a
concentration gradient created by FAAH activity. We conclude that
endocannabinoids are present in the goldfish retina and underlay the
electrophysiological effects of cannabinoid ligands previously shown on
goldfish cones and bipolar cells.
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Affiliation(s)
- Sherrye T Glaser
- Department of Biochemistry and Cell Biology, Stony Brook University, New York 11794-5230, USA
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22
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Abstract
The molecular organization of ribbon synapses in photoreceptors and ON bipolar cells is reviewed in relation to the process of neurotransmitter release. The interactions between ribbon synapse-associated proteins, synaptic vesicle fusion machinery and the voltage-gated calcium channels that gate transmitter release at ribbon synapses are discussed in relation to the process of synaptic vesicle exocytosis. We describe structural and mechanistic specializations that permit the ON bipolar cell to release transmitter at a much higher rate than the photoreceptor does, under in vivo conditions. We also consider the modulation of exocytosis at photoreceptor synapses, with an emphasis on the regulation of calcium channels.
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Affiliation(s)
- Ruth Heidelberger
- Department of Neurobiology & Anatomy, University of Texas Health Science Center at Houston, Houston, TX 77030 USA
| | - Wallace B. Thoreson
- Department of Ophthalmology & Visual Sciences and Department of Pharmacology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul Witkovsky
- Department of Ophthalmology and Department of Physiology & Neuroscience, New York University School of Medicine, New York, NY 10016, USA
- *Corresponding author. Tel: +1 212 263 6488; fax: +1 212 263 7602. E-mail address: (P. Witkovsky)
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23
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Fan SF, Yazulla S. Reciprocal inhibition of voltage-gated potassium currents (IK(V)) by activation of cannabinoid CB1and dopamine D1receptors in ON bipolar cells of goldfish retina. Vis Neurosci 2005; 22:55-63. [PMID: 15842741 DOI: 10.1017/s0952523805221089] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Indexed: 11/06/2022]
Abstract
Cannabinoid CB1receptor (viaGs) and dopamine D2receptor (viaGi/o) antagonistically modulate goldfish cone membrane currents. As ON bipolar cells have CB1and D1receptors, but not D2receptors, we focused on whether CB1receptor agonist and dopamine interact to modulate voltage-dependent outward membrane K+currentsIK(V)of the ON mixed rod/cone (Mb) bipolar cells. Whole-cell currents were recorded from Mb bipolar cells in goldfish retinal slices. Mb bipolar cells were identified by intracellular filling with Lucifer yellow. The bath solution was calcium-free and contained 1 mM cobalt to block indirect calcium-dependent effects. Dopamine (10 μM) consistently increasedIK(V)by a factor of 1.57 ± 0.12 (S.E.M.,n= 15). A CB receptor agonist, WIN 55212-2 (0.25–1 μM), had no effect, but 4 μM WIN 55212-2 suppressedIK(V)by 60%. IfIK(V)was first increased by 10 μM dopamine, application of WIN 55212-2 (0.25–1 μM) reversibly blocked the effect of dopamine even though these concentrations of WIN 55212-2 had no effect of their own. If WIN 55212-2 was applied first and dopamine (10 μM) was added to the WIN-containing solution, 0.1 μM WIN 55212-2 blocked the effect of dopamine. All effects of WIN 55212-2 were blocked by coapplication of SR 141716A (CB1antagonist) and pretreatment with pertussis toxin (blocker of Gi/o) indicating actionviaCB1receptor activation of G protein Gi/o. Coactivation of CB1and D1receptors on Mb bipolar cells produces reciprocal effects onIK(V). The CB1-evoked suppression ofIK(V)is mediated by G protein Gi/o, whereas the D1-evoked enhancement is mediated by G protein Gs. As dopamine is a retinal “light” signal, these data support our notion that endocannabinoids function as a “dark” signal, interacting with dopamine to set retinal sensitivity.
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Affiliation(s)
- Shih-Fang Fan
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794-5230, USA
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