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Hawkins SJ, Gärtner Y, Offner T, Weiss L, Maiello G, Hassenklöver T, Manzini I. The olfactory network of larval Xenopus laevis regenerates accurately after olfactory nerve transection. Eur J Neurosci 2024; 60:3719-3741. [PMID: 38758670 DOI: 10.1111/ejn.16375] [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: 12/07/2023] [Revised: 04/10/2024] [Accepted: 04/14/2024] [Indexed: 05/19/2024]
Abstract
Across vertebrate species, the olfactory epithelium (OE) exhibits the uncommon feature of lifelong neuronal turnover. Epithelial stem cells give rise to new neurons that can adequately replace dying olfactory receptor neurons (ORNs) during developmental and adult phases and after lesions. To relay olfactory information from the environment to the brain, the axons of the renewed ORNs must reconnect with the olfactory bulb (OB). In Xenopus laevis larvae, we have previously shown that this process occurs between 3 and 7 weeks after olfactory nerve (ON) transection. In the present study, we show that after 7 weeks of recovery from ON transection, two functionally and spatially distinct glomerular clusters are reformed in the OB, akin to those found in non-transected larvae. We also show that the same odourant response tuning profiles observed in the OB of non-transected larvae are again present after 7 weeks of recovery. Next, we show that characteristic odour-guided behaviour disappears after ON transection but recovers after 7-9 weeks of recovery. Together, our findings demonstrate that the olfactory system of larval X. laevis regenerates with high accuracy after ON transection, leading to the recovery of odour-guided behaviour.
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Affiliation(s)
- Sara J Hawkins
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Yvonne Gärtner
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Thomas Offner
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
| | - Lukas Weiss
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
| | - Guido Maiello
- Department of Experimental Psychology, Justus Liebig University Gießen, Gießen, Germany
- School of Psychology, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Thomas Hassenklöver
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
| | - Ivan Manzini
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus Liebig University Gießen, Gießen, Germany
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2
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Dieris M, Kowatschew D, Hassenklöver T, Manzini I, Korsching SI. Calcium imaging of adult olfactory epithelium reveals amines as important odor class in fish. Cell Tissue Res 2024; 396:95-102. [PMID: 38347202 PMCID: PMC10997700 DOI: 10.1007/s00441-024-03859-w] [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: 10/18/2023] [Accepted: 12/29/2023] [Indexed: 04/06/2024]
Abstract
The odor space of aquatic organisms is by necessity quite different from that of air-breathing animals. The recognized odor classes in teleost fish include amino acids, bile acids, reproductive hormones, nucleotides, and a limited number of polyamines. Conversely, a significant portion of the fish olfactory receptor repertoire is composed of trace amine-associated receptors, generally assumed to be responsible for detecting amines. Zebrafish possess over one hundred of these receptors, but the responses of olfactory sensory neurons to amines have not been known so far. Here we examined odor responses of zebrafish olfactory epithelial explants at the cellular level, employing calcium imaging. We report that amines elicit strong responses in olfactory sensory neurons, with a time course characteristically different from that of ATP-responsive (basal) cells. A quantitative analysis of the laminar height distribution shows amine-responsive cells undistinguishable from ciliated neurons positive for olfactory marker protein. This distribution is significantly different from those measured for microvillous neurons positive for transient receptor potential channel 2 and basal cells positive for proliferating cell nuclear antigen. Our results suggest amines as an important odor class for teleost fish.
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Affiliation(s)
- M Dieris
- Institute of Genetics, Faculty of Mathematics and Natural Sciences of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany
| | - D Kowatschew
- Institute of Genetics, Faculty of Mathematics and Natural Sciences of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany
| | - T Hassenklöver
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Göttingen Germany, and Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
- Current address: Department of Animal Physiology and Molecular Biomedicine, Institute of Animal Physiology, Justus-Liebig-University Gießen, Gießen, Germany
| | - I Manzini
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Göttingen Germany, and Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
- Current address: Department of Animal Physiology and Molecular Biomedicine, Institute of Animal Physiology, Justus-Liebig-University Gießen, Gießen, Germany
| | - S I Korsching
- Institute of Genetics, Faculty of Mathematics and Natural Sciences of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany.
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3
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Gonçalves AM, Santana CC, Santos LFJD, Colosio RR, Balbuena TS, Pizauro JM. Identification and characterization of acid and alkaline phosphatases and protein phosphatases in L. catesbeianus tail during metamorphosis. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00877-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Colosio RR, Santos LFJ, Gonçalves AM, Santana CC, Pavarina GC, Pizauro JM. Enzymatic activity of bone markers on Lithobates catesbeianus (Shaw, 1802) growth during the ossification process. BRAZ J BIOL 2021; 84:e251970. [PMID: 34705954 DOI: 10.1590/1519-6984.251970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/15/2021] [Indexed: 11/22/2022] Open
Abstract
In order to better understand the ossification processes in anurans our study was carried out on tadpoles and adults of Lithobates catesbeianus. In this sense, we characterized the kinetic properties of alkaline phosphatase with p-nitrophenylphosphatase (pNPP) and pyrophosphate (PPi) and evaluated the activities of tartrate-resistant acid phosphatase and acid phosphatase. The enzyme extracts were obtained from tadpoles and adult femurs, which were divided into epiphysis and diaphysis. After homogenization, the samples were submitted to differential centrifugation to obtain cell membranes and, further, to phospholipase C (PIPLC) treatment, to remove membrane-bound proteins anchored by phosphatidylinositol. The average of specific activity for pNPP hydrolysis (at pH 10.5) by alkaline phosphatase released by phosphatidylinositol-specific phospholipase C (PIPLC) from Bacillus cereus among different bone regions at different animal ages was 1,142.57 U.mg-1, while for PPi hydrolysis (at pH 8.0), it was 1,433.82 U.mg-1. Among the compounds tested for enzymatic activity, the one that influenced the most was EDTA, with approximately 67% of inhibition for pNPPase activity and 77% for PPase activity. In the case of kinetic parameters, the enzyme showed a "Michaelian" behavior for pNPP and PPi hydrolysis. The Km value was around 0.6mM for pNPPase activity and ranged from 0.01 to 0.11mM for PPase activity, indicating that the enzyme has a higher affinity for this substrate. The study of pNPP and PPi hydrolysis by the enzyme revealed that the optimum pH of actuation for pNPP was 10.5, while for PPi, which is considered the true substrate of alkaline phosphatase, was 8.0, close to the physiological value. The results show that regardless of the ossification type that occurs, the same enzyme or isoenzymes act on the different bone regions and different life stages of anurans. The similarity of the results of studies with other vertebrates shows that anurans can be considered excellent animal models for the study of biological calcification.
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Affiliation(s)
- R R Colosio
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brasil.,Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Química, Departamento de Bioquímica e Química Orgânica, Araraquara, SP, Brasil
| | - L F J Santos
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brasil.,Faculdade de Tecnologia - FATEC, Ribeirão Preto, SP, Brasil
| | - A M Gonçalves
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Química, Departamento de Bioquímica e Química Orgânica, Araraquara, SP, Brasil.,Universidade de Araraquara - UNIARA, Departamento de Ciências Biológicas e de Saúde, Araraquara, SP, Brasil
| | - C C Santana
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brasil.,Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Química, Departamento de Bioquímica e Química Orgânica, Araraquara, SP, Brasil
| | - G C Pavarina
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brasil
| | - J M Pizauro
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brasil.,Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Química, Departamento de Bioquímica e Química Orgânica, Araraquara, SP, Brasil
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5
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Bryche B, Baly C, Meunier N. Modulation of olfactory signal detection in the olfactory epithelium: focus on the internal and external environment, and the emerging role of the immune system. Cell Tissue Res 2021; 384:589-605. [PMID: 33961125 PMCID: PMC8102665 DOI: 10.1007/s00441-021-03467-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/26/2021] [Indexed: 12/18/2022]
Abstract
Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing environment. Part of these adaptations includes changes of odorant detection by olfactory sensory neurons localized in the olfactory epithelium. It is now well established that internal signals such as hormones, neurotransmitters, or paracrine signals directly affect the electric activity of olfactory neurons. Furthermore, recent data have shown that activity-dependent survival of olfactory neurons is important in the olfactory epithelium. Finally, as olfactory neurons are directly exposed to environmental toxicants and pathogens, the olfactory epithelium also interacts closely with the immune system leading to neuroimmune modulations. Here, we review how detection of odorants can be modulated in the vertebrate olfactory epithelium. We choose to focus on three cellular types of the olfactory epithelium (the olfactory sensory neuron, the sustentacular and microvillar cells) to present the diversity of modulation of the detection of odorant in the olfactory epithelium. We also present some of the growing literature on the importance of immune cells in the functioning of the olfactory epithelium, although their impact on odorant detection is only just beginning to be unravelled.
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Affiliation(s)
- Bertrand Bryche
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France
| | - Christine Baly
- Université Paris Saclay, INRAE, UVSQ, BREED, 78350, Jouy-en-Josas, France
| | - Nicolas Meunier
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France.
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6
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Dibattista M, Pifferi S, Menini A, Reisert J. Alzheimer's Disease: What Can We Learn From the Peripheral Olfactory System? Front Neurosci 2020; 14:440. [PMID: 32508565 PMCID: PMC7248389 DOI: 10.3389/fnins.2020.00440] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/09/2020] [Indexed: 01/01/2023] Open
Abstract
The sense of smell has been shown to deteriorate in patients with some neurodegenerative disorders. In Parkinson's disease (PD) and Alzheimer's disease (AD), decreased ability to smell is associated with early disease stages. Thus, olfactory neurons in the nose and olfactory bulb (OB) may provide a window into brain physiology and pathophysiology to address the pathogenesis of neurodegenerative diseases. Because nasal olfactory receptor neurons regenerate throughout life, the olfactory system offers a broad variety of cellular mechanisms that could be altered in AD, including odorant receptor expression, neurogenesis and neurodegeneration in the olfactory epithelium, axonal targeting to the OB, and synaptogenesis and neurogenesis in the OB. This review focuses on pathophysiological changes in the periphery of the olfactory system during the progression of AD in mice, highlighting how the olfactory epithelium and the OB are particularly sensitive to changes in proteins and enzymes involved in AD pathogenesis. Evidence reviewed here in the context of the emergence of other typical pathological changes in AD suggests that olfactory impairments could be used to understand the molecular mechanisms involved in the early phases of the pathology.
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Affiliation(s)
- Michele Dibattista
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari A. Moro, Bari, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
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7
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Henriques T, Agostinelli E, Hernandez-Clavijo A, Maurya DK, Rock JR, Harfe BD, Menini A, Pifferi S. TMEM16A calcium-activated chloride currents in supporting cells of the mouse olfactory epithelium. J Gen Physiol 2019; 151:954-966. [PMID: 31048412 PMCID: PMC6605691 DOI: 10.1085/jgp.201812310] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/08/2019] [Accepted: 04/15/2019] [Indexed: 12/15/2022] Open
Abstract
Glial-like supporting (or sustentacular) cells are important constituents of the olfactory epithelium that are involved in several physiological processes such as production of endocannabinoids, insulin, and ATP and regulation of the ionic composition of the mucus layer that covers the apical surface of the olfactory epithelium. Supporting cells express metabotropic P2Y purinergic receptors that generate ATP-induced Ca2+ signaling through the activation of a PLC-mediated cascade. Recently, we reported that a subpopulation of supporting cells expresses also the Ca2+-activated Cl- channel TMEM16A. Here, we sought to extend our understanding of a possible physiological role of this channel in the olfactory system by asking whether Ca2+ can activate Cl- currents mediated by TMEM16A. We use whole-cell patch-clamp analysis in slices of the olfactory epithelium to measure dose-response relations in the presence of various intracellular Ca2+ concentrations, ion selectivity, and blockage. We find that knockout of TMEM16A abolishes Ca2+-activated Cl- currents, demonstrating that TMEM16A is essential for these currents in supporting cells. Also, by using extracellular ATP as physiological stimuli, we found that the stimulation of purinergic receptors activates a large TMEM16A-dependent Cl- current, indicating a possible role of TMEM16A in ATP-mediated signaling. Altogether, our results establish that TMEM16A-mediated currents are functional in olfactory supporting cells and provide a foundation for future work investigating the precise physiological role of TMEM16A in the olfactory system.
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Affiliation(s)
- Tiago Henriques
- Neurobiology Group, International School for Advanced Studies, Trieste, Italy
| | - Emilio Agostinelli
- Neurobiology Group, International School for Advanced Studies, Trieste, Italy
| | | | | | - Jason R Rock
- Center for Regenerative Medicine, Boston University School of Medicine, Boston, MA
| | - Brian D Harfe
- Department of Molecular Genetics and Microbiology Genetics Institute, University of Florida, College of Medicine, Gainesville, FL
| | - Anna Menini
- Neurobiology Group, International School for Advanced Studies, Trieste, Italy
| | - Simone Pifferi
- Neurobiology Group, International School for Advanced Studies, Trieste, Italy
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8
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Rotermund N, Schulz K, Hirnet D, Lohr C. Purinergic Signaling in the Vertebrate Olfactory System. Front Cell Neurosci 2019; 13:112. [PMID: 31057369 PMCID: PMC6477478 DOI: 10.3389/fncel.2019.00112] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/07/2019] [Indexed: 12/15/2022] Open
Abstract
Adenosine 5'-triphosphate (ATP) is an ubiquitous co-transmitter in the vertebrate brain. ATP itself, as well as its breakdown products ADP and adenosine are involved in synaptic transmission and plasticity, neuron-glia communication and neural development. Although purinoceptors have been demonstrated in the vertebrate olfactory system by means of histological techniques for many years, detailed insights into physiological properties and functional significance of purinergic signaling in olfaction have been published only recently. We review the current literature on purinergic neuromodulation, neuron-glia interactions and neurogenesis in the vertebrate olfactory system.
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Affiliation(s)
- Natalie Rotermund
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Kristina Schulz
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Daniela Hirnet
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
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9
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Sato K, Sorensen PW. The Chemical Sensitivity and Electrical Activity of Individual Olfactory Sensory Neurons to a Range of Sex Pheromones and Food Odors in the Goldfish. Chem Senses 2018; 43:249-260. [PMID: 29514213 PMCID: PMC5913646 DOI: 10.1093/chemse/bjy016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although it is well established that the olfactory epithelium of teleost fish detects at least 6 classes of biologically relevant odorants using 5 types of olfactory sensory neurons (OSNs), little is understood about the specificity of individual OSNs and thus how they encode identity of natural odors. In this study, we used in vivo extracellular single-unit recording to examine the odor responsiveness and physiological characteristics of 109 individual OSNs in mature male goldfish to a broad range of biological odorants including feeding stimuli (amino acids, polyamines, nucleotides), sex pheromones (sex steroids, prostaglandins [PGs]), and a putative social cue (bile acids). Sixty-one OSNs were chemosensitive, with over half of these (36) responding to amino acids, 7 to polyamines, 7 to nucleotides, 5 to bile acids, 9 to PGs, and 7 to sex steroids. Approximately a quarter of the amino acid-sensitive units also responded to polyamines or nucleotides. Three of 6 amino acid-sensitive units responded to more than 1 amino acid compound, and 5 sex pheromone-sensitive units detected just 1 sex pheromone. While pheromone-sensitive OSNs also responded to the adenylyl cyclase activator, forskolin, amino acid-sensitive OSNs responded to either forskolin or a phospholipase C activator, imipramine. Most OSNs responded to odorants and activators with excitation. Our results suggest that pheromone information is encoded by OSNs specifically tuned to single sex pheromones and employ adenylyl cyclase, suggestive of a labeled-line organization, while food information is encoded by a combination of OSNs that use both adenylyl cyclase and phospholipase C and are often less specifically tuned.
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Affiliation(s)
- Koji Sato
- Okazaki Institute for Integrative Bioscience, Biosensing Research, Higashiyama Myodaijicho, Okazaki, Aichi, Japan
| | - Peter W Sorensen
- Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St Paul, MN, USA
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An Adenosine Receptor for Olfaction in Fish. Curr Biol 2017; 27:1437-1447.e4. [PMID: 28502661 DOI: 10.1016/j.cub.2017.04.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/14/2017] [Accepted: 04/10/2017] [Indexed: 11/22/2022]
Abstract
Nucleotides released from food sources into environmental water are supposed to act as feeding cues for many fish species. However, it remains unknown how fish can sensitively detect those nucleotides. Here we discover a novel olfactory mechanism for ATP sensing in zebrafish. Upon entering into the nostril, ATP is efficiently converted into adenosine through enzymatic reactions of two ecto-nucleotidases expressed in the olfactory epithelium. Adenosine subsequently activates a small population of olfactory sensory neurons expressing a novel adenosine receptor A2c that is unique to fishes and amphibians. The information is then transmitted to a single glomerulus in the olfactory bulb and further to four regions in higher olfactory centers. These results provide conclusive evidence for a sophisticated enzyme-linked receptor mechanism underlying detection of ATP as a food-derived attractive odorant linking to foraging behavior that is crucial and common to aquatic lower vertebrates.
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Santos LFJD, de Oliveira-Bahia VRL, Nakaghi LSO, De Stefani MV, Gonçalves AM, Junior JMP. Ontogeny of the Digestive Enzymes of Tadpoles ofLithobates catesbeianus. COPEIA 2016. [DOI: 10.1643/cg-16-432] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Gonçalves AM, Santos LFJ, Santana CC, Colosio RR, Pizauro JM. Activity of Tail Phosphatases: A Study during Growth and Metamorphosis ofLithobates catesbeianus. COPEIA 2015. [DOI: 10.1643/ot-14-131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction. Neuroscience 2015; 300:539-53. [PMID: 26037800 DOI: 10.1016/j.neuroscience.2015.05.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/21/2015] [Accepted: 05/23/2015] [Indexed: 11/22/2022]
Abstract
Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium have not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia-like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1- and CB2- receptor-deficient (CB1(-/-)/CB2(-/-)) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1(-/-)/CB2(-/-) mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1(-/-)/CB2(-/-) mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted.
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Dittrich K, Sansone A, Hassenklöver T, Manzini I. Purinergic receptor-induced Ca2+ signaling in the neuroepithelium of the vomeronasal organ of larval Xenopus laevis. Purinergic Signal 2013; 10:327-36. [PMID: 24271060 PMCID: PMC4040167 DOI: 10.1007/s11302-013-9402-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/04/2013] [Indexed: 01/07/2023] Open
Abstract
Purinergic signaling has considerable impact on the functioning of the nervous system, including the special senses. Purinergic receptors are expressed in various cell types in the retina, cochlea, taste buds, and the olfactory epithelium. The activation of these receptors by nucleotides, particularly adenosine-5′-triphosphate (ATP) and its breakdown products, has been shown to tune sensory information coding to control the homeostasis and to regulate the cell turnover in these organs. While the purinergic system of the retina, cochlea, and taste buds has been investigated in numerous studies, the available information about purinergic signaling in the olfactory system is rather limited. Using functional calcium imaging, we identified and characterized the purinergic receptors expressed in the vomeronasal organ of larval Xenopus laevis. ATP-evoked activity in supporting and basal cells was not dependent on extracellular Ca2+. Depletion of intracellular Ca2+ stores disrupted the responses in both cell types. In addition to ATP, supporting cells responded also to uridine-5′-triphosphate (UTP) and adenosine-5′-O-(3-thiotriphosphate) (ATPγS). The response profile of basal cells was considerably broader. In addition to ATP, they were activated by ADP, 2-MeSATP, 2-MeSADP, ATPγS, UTP, and UDP. Together, our findings suggest that supporting cells express P2Y2/P2Y4-like purinergic receptors and that basal cells express multiple P2Y receptors. In contrast, vomeronasal receptor neurons were not sensitive to nucleotides, suggesting that they do not express purinergic receptors. Our data provide the basis for further investigations of the physiological role of purinergic signaling in the vomeronasal organ and the olfactory system in general.
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Affiliation(s)
- Katarina Dittrich
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
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Gascuel J, Amano T. Exotic models may offer unique opportunities to decipher specific scientific question: the case of Xenopus olfactory system. Anat Rec (Hoboken) 2013; 296:1453-61. [PMID: 23904180 DOI: 10.1002/ar.22749] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 06/18/2013] [Indexed: 11/10/2022]
Abstract
The fact that olfactory systems are highly conserved in all animal species from insects to mammals allow the generalization of findings from one species to another. Most of our knowledge about the anatomy and physiology of the olfactory system comes from data obtained in a very limited number of biological models such as rodents, Zebrafish, Drosophila, and a worm, Caenorhabditis elegans. These models have proved useful to answer most questions in the field of olfaction, and thus concentrating on these few models appear to be a pragmatic strategy. However, the diversity of the organization and physiology of the olfactory system amongst phyla appear to be greater than generally assumed and the four models alone may not be sufficient to address all the questions arising from the study of olfaction. In this article, we will illustrate the idea that we should take advantage of biological diversity to address specific scientific questions and will show that the Xenopus olfactory system is a very good model to investigate: first, olfaction in aerial versus aquatic conditions and second, mechanisms underlying postnatal reorganization of the olfactory system especially those controlled by tyroxine hormone.
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Affiliation(s)
- Jean Gascuel
- CNRS UMR 6265 Centre des sciences du goût et de l'alimentation, Dijon France.
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Li F, Cao J, Zhou M. NTPDase2+ Cells Generate Lingual Epithelia and Papillae. Front Genet 2012; 3:255. [PMID: 23293651 PMCID: PMC3536025 DOI: 10.3389/fgene.2012.00255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 10/29/2012] [Indexed: 11/13/2022] Open
Abstract
The tongue epithelium is one of the most rapidly self-renewing tissues in adult mammals. Multiple stem cell populations are currently believed to exist in tongue epithelia. Keratin 14 (K14) positive cells differentiate into either lingual epithelia or lingual papillae, while ecto-nucleoside triphosphate diphosphohydrolase 2 (NTPDase2) is associated with neural stem cells and astrocyte-like cells ensheathing the migrating neuroblasts. Here, using a transgenic mouse expressing rtTA from the mouse NTPDase2 promoter, we generated an inducible model by treatment with Doxycycline. By immunohistochemical analysis and in situ hybridization, we found exclusive expression of NTPDase2 in lingual epithelia and lingual papillae. Using inducible genetic cell fate mapping, we further showed that the NTPDase2+ cells generated lingual papillae and epithelia in the adult tongue. Finally, building on our previously proposed paradigm of cell migration stream, a model is further described here for lingual epithelia cell genesis. In short, the current results not only extend our understanding of the cell migration stream in lingual epithelia and lingual papillae, but they also support the concept of multiple stem cell populations in lingual epithelia and papillae.
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Affiliation(s)
- Feng Li
- School of Medicine, Shanghai Jiao Tong University Shanghai, China
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17
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Lucero MT. Peripheral modulation of smell: fact or fiction? Semin Cell Dev Biol 2012; 24:58-70. [PMID: 22986099 DOI: 10.1016/j.semcdb.2012.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 09/06/2012] [Indexed: 01/01/2023]
Abstract
Despite studies dating back 30 or more years showing modulation of odorant responses at the level of the olfactory epithelium, most descriptions of the olfactory system infer that odorant signals make their way from detection by cilia on olfactory sensory neurons to the olfactory bulb unaltered. Recent identification of multiple subtypes of microvillar cells and identification of neuropeptide and neurotransmitter expression in the olfactory mucosa add to the growing body of literature for peripheral modulation in the sense of smell. Complex mechanisms including perireceptor events, modulation of sniff rates, and changes in the properties of sensory neurons match the sensitivity of olfactory sensory neurons to the external odorant environment, internal nutritional status, reproductive status, and levels of arousal or stress. By furthering our understanding of the players mediating peripheral olfaction, we may open the door to novel approaches for modulating the sense of smell in both health and disease.
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Affiliation(s)
- Mary T Lucero
- Department of Physiology, School of Medicine, University of Utah, 420 Chipeta Way Ste, 1700 Salt Lake City, UT 84108, USA.
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18
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Vick JS, Delay RJ. ATP excites mouse vomeronasal sensory neurons through activation of P2X receptors. Neuroscience 2012; 220:341-50. [PMID: 22698690 DOI: 10.1016/j.neuroscience.2012.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 05/17/2012] [Accepted: 06/01/2012] [Indexed: 11/19/2022]
Abstract
Purinergic signaling through activation of P2X and P2Y receptors is critically important in the chemical senses. In the mouse main olfactory epithelium (MOE), adenosine 5'-triphosphate (ATP) elicits an increase in intracellular calcium ([Ca(2+)](I)) and reduces the responsiveness of olfactory sensory neurons to odorants through activation of P2X and P2Y receptors. We investigated the role of purinergic signaling in vomeronasal sensory neuron (VSN)s from the mouse vomeronasal organ (VNO), an olfactory organ distinct from the MOE that responds to many conspecific chemical cues. Using a combination of calcium imaging and patch-clamp electrophysiology with isolated VSNs, we demonstrated that ATP elicits an increase in [Ca(2+)](I) and an inward current with similar EC(50)s. Neither adenosine nor the P2Y receptor ligands adenosine 5'-diphosphate, uridine 5'-triphosphate, and uridine-5'-disphosphate could mimic either effect of ATP. Moreover, the increase in [Ca(2+)](I) required the presence of extracellular calcium and the inward current elicited by ATP was partially blocked by the P2X receptor antagonists pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate and 2',3'-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate. Consistent with the activation of P2X receptors, we detected gene expression of the P2X1 and 3 receptors in the VNO by Reverse transcription polymerase chain reaction (RT-PCR). When co-delivered with dilute urine, a natural stimulus, ATP significantly increased the inward current above that elicited by dilute urine or ATP alone. Mechanical stimulation of the VNO induced the release of ATP, detected by luciferin-luciferase luminometry, and this release of ATP was completely abolished in the presence of the connexin/pannexin hemichannel blocker, carbenoxolone. We conclude that the release of ATP could occur during the activity of the vasomotor pump that facilitates the movement of chemicals into the VNO for detection by VSNs. This mechanism could lead to a global increase in excitability and the chemosensory response in VSNs through activation of P2X receptors.
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Affiliation(s)
- J S Vick
- Department of Biology and Vermont Chemosensory Group, University of Vermont, Marsh Life Science Building, 109 Carrigan Drive, Burlington, VT 05405, United States.
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19
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Breunig E, Kludt E, Czesnik D, Schild D. The styryl dye FM1-43 suppresses odorant responses in a subset of olfactory neurons by blocking cyclic nucleotide-gated (CNG) channels. J Biol Chem 2011; 286:28041-8. [PMID: 21646359 DOI: 10.1074/jbc.m111.233890] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many olfactory receptor neurons use a cAMP-dependent transduction mechanism to transduce odorants into depolarizations. This signaling cascade is characterized by a sequence of two currents: a cation current through cyclic nucleotide-gated channels followed by a chloride current through calcium-activated chloride channels. To date, it is not possible to interfere with these generator channels under physiological conditions with potent and specific blockers. In this study we identified the styryl dye FM1-43 as a potent blocker of native olfactory cyclic nucleotide-gated channels. Furthermore, we characterized this substance to stain olfactory receptor neurons that are endowed with cAMP-dependent transduction. This allows optical differentiation and pharmacological interference with olfactory receptor neurons at the level of the signal transduction.
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Affiliation(s)
- Esther Breunig
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen,37073 Göttingen, Germany
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20
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Jia C, Cussen AR, Hegg CC. ATP differentially upregulates fibroblast growth factor 2 and transforming growth factor α in neonatal and adult mice: effect on neuroproliferation. Neuroscience 2010; 177:335-46. [PMID: 21187124 DOI: 10.1016/j.neuroscience.2010.12.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 12/21/2010] [Indexed: 02/05/2023]
Abstract
Multiple neurotrophic factors play a role in proliferation, differentiation and survival in the olfactory epithelium (OE); however, the signaling cascade has not been fully elucidated. We tested the hypotheses that ATP induces the synthesis and secretion of two neurotrophic factors, fibroblast growth factor 2 (FGF2) and transforming growth factor alpha (TGFα), and that these neurotrophic factors have a role in inducing proliferation. Protein levels of FGF2 and TGFα were increased 20 h post-intranasal instillation of ATP compared to vehicle control in adult Swiss Webster mice. Pre-intranasal treatment with purinergic receptor antagonist pyridoxal-phosphate-6-azophenyl-20,40-disulfonic acid (PPADS) significantly blocked this ATP-induced increase, indicating that upregulation of FGF2 and TGFα expression is mediated by purinergic receptor activation. However, in neonatal mouse, intranasal instillation of ATP significantly increased the protein levels of FGF2, but not TGFα. Likewise, ATP evoked the secretion of FGF2, but not TGFα, from neonatal mouse olfactory epithelial slices and PPADS significantly blocked ATP-evoked FGF2 release. To determine the role of FGF2 and TGFα in inducing proliferation, 5-bromo-2-deoxyuridine (BrdU) incorporation was examined in adult olfactory epithelium. Intranasal treatment with FGF receptor inhibitor PD173074 or epidermal growth factor receptor inhibitor AG1478 following ATP instillation significantly blocked ATP-induced BrdU incorporation. Collectively, these data demonstrate that ATP induces proliferation in adult mouse olfactory epithelium by promoting FGF2 and TGFα synthesis and activation of their receptors. These data suggest that different mechanisms regulate neurogenesis in neonatal and adult OE, and FGF2 and TGFα may have different roles throughout development.
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Affiliation(s)
- C Jia
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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NPY mediates ATP-induced neuroproliferation in adult mouse olfactory epithelium. Neurobiol Dis 2010; 38:405-13. [PMID: 20211262 DOI: 10.1016/j.nbd.2010.02.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 02/22/2010] [Accepted: 02/27/2010] [Indexed: 11/20/2022] Open
Abstract
In the CNS, ATP is released upon injury and promotes neuroproliferation via purinergic receptors. In the olfactory epithelium, ATP promotes the synthesis and release of neurotrophic factor NPY in neonates and induces neuroproliferation in neonatal and adult mice. We tested the hypothesis that NPY is involved in ATP-induced neuroproliferation in adult mice olfactory epithelium. Intranasal instillation of ATP significantly increased protein levels and number of NPY(+) cells. Pre-intranasal instillation of purinergic receptor antagonist PPADS significantly reduced ATP-induced upregulation of NPY. Intranasal instillation of NPY-Y1 receptor antagonist BIBP3226 following ATP instillation significantly inhibited the ATP-induced increase in BrdU incorporation, suggesting that NPY is released after ATP instillation and activates Y1 receptors to promote neuroproliferation. These data indicate that ATP initiates neuroproliferation via NPY upregulation, NPY release, and Y1 receptor activation, and suggests that the olfactory epithelium is good model to study neuroregenerative mechanisms in the CNS.
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Hassenklöver T, Schwartz P, Schild D, Manzini I. Purinergic signaling regulates cell proliferation of olfactory epithelium progenitors. Stem Cells 2010; 27:2022-31. [PMID: 19544419 DOI: 10.1002/stem.126] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the olfactory epithelium (OE) continuous neurogenesis is maintained throughout life. The OE is in direct contact with the external environment, and its cells are constantly exposed to pathogens and noxious substances. To maintain a functional sense of smell the OE has evolved the ability to permanently replenish olfactory receptor neurons and sustentacular cells lost during natural turnover. A cell population residing in the most basal part of the OE, the so-called basal cells (BCs), keep up this highly regulated genesis of new cells. The population of BCs is thought to include both the stem cells of the OE and various progenitor cells. In recent years a number of regulatory factors that positively and/or negatively regulate the proliferation within the OE have been identified, but a thorough comprehension of the complex interplay of these regulatory factors and the role of the different epithelial cell types is still illusive. Combining labeling techniques, immunohistochemistry, electron microscopy, functional calcium imaging, and a bromo-2'-deoxyuridine incorporation assay, we show for the first time that purinergic receptors are expressed in BCs of the OE of larval Xenopus laevis and that nucleotide-induced Ca(2+) signaling in these cells is involved in the regulation of the cell turnover in the OE. Our data contribute to a better understanding of the regulation of the cell turnover in the OE in particular and also of how the proliferation of neuronal progenitor cells is regulated in general.
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Affiliation(s)
- Thomas Hassenklöver
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen, Göttingen, Germany
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23
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Gliem S, Schild D, Manzini I. Highly specific responses to amine odorants of individual olfactory receptor neurons in situ. Eur J Neurosci 2009; 29:2315-26. [PMID: 19490026 DOI: 10.1111/j.1460-9568.2009.06778.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The main olfactory system of larval Xenopus laevis is made up of at least two subsystems consisting of subsets of olfactory receptor neurons (ORNs) with different transduction mechanisms. One ORN subset lacks the canonical cAMP transduction pathway and responds to amino acid odorants. The second subset has the cAMP transduction pathway but as yet suitable odorants are unknown. Here we report the identification of amines as proper olfactory stimuli for larval X. laevis using functional Ca(2+) imaging and slice preparations of the olfactory system. The response profiles of individual ORNs to a number of amines were extremely complex and mostly highly specific. The great majority of amine-sensitive ORNs responded also to forskolin, an activator of the olfactory cAMP transduction pathway. Most amine-induced responses could be attenuated by the cyclic nucleotide-gated channel inhibitor LY83583. This confirms that most amine-responsive olfactory receptors (ORs) are coupled to the cAMP-dependent transduction pathway. Furthermore, we show that trace amine-associated receptors (TAARs), which have been shown to act as specific ORs for amines in mammals, are expressed in the olfactory organ of X. laevis. The TAARs expressed in Xenopus cannot, however, explain the complex responses of individual ORNs to amines because there are too few of them. This indicates that, in addition to TAARs, there must be other receptor families involved in the detection of amines.
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Affiliation(s)
- S Gliem
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, Göttingen, Germany
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24
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Hegg CC, Irwin M, Lucero MT. Calcium store-mediated signaling in sustentacular cells of the mouse olfactory epithelium. Glia 2009; 57:634-44. [PMID: 18942758 DOI: 10.1002/glia.20792] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sustentacular cells have structural features that allude to functions of secretion, absorption, phagocytosis, maintenance of extracellular ionic gradients, metabolism of noxious chemicals, and regulation of cell turnover. We present data detailing their dynamic activity. We show, using a mouse olfactory epithelium slice model, that sustentacular cells are capable of generating two types of calcium signals: intercellular calcium waves where elevations in intracellular calcium propagate between neighboring cells, and intracellular calcium oscillations consisting of repetitive elevations in intracellular calcium confined to single cells. Sustentacular cells exhibited rapid, robust increases in intracellular calcium in response to G-protein coupled muscarinic and purinergic receptor stimulation. In a subpopulation of sustentacular cells, oscillatory calcium transients were evoked. We pharmacologically characterized the properties of purinergic-evoked increases in intracellular calcium. Calcium transients were elicited by release from intracellular stores and were not dependent on extracellular calcium. BAPTA-AM, a cytosolic calcium chelator, and cyclopiazonic acid, an endoplasmic reticulum Ca(2+)-ATPase inhibitor irreversibly blocked the purinergic-induced calcium transient. Phospholipase C antagonist U73122 inhibited the purinergic-evoked calcium transient. 2-Aminoethoxydiphenyl borate, an inositol-1,4,5-trisphosphate (IP(3)) receptor antagonist, and the ryanodine receptor (RyR) antagonists tetracaine and ryanodine, inhibited the UTP-induced calcium transients. Collectively, these data suggest that activation of the phospholipase C pathway, IP(3)-mediated calcium release, and subsequent calcium-induced-calcium release is involved in ATP-elicited increases in intracellular calcium. Our findings indicate that sustentacular cells are not static support cells, and, like glia in the central nervous system, have complex calcium signaling.
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Affiliation(s)
- Colleen Cosgrove Hegg
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA.
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25
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Kanekar S, Jia C, Hegg CC. Purinergic receptor activation evokes neurotrophic factor neuropeptide Y release from neonatal mouse olfactory epithelial slices. J Neurosci Res 2009; 87:1424-34. [PMID: 19115410 DOI: 10.1002/jnr.21954] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
One premise regarding the mechanism of injury-evoked neuroregeneration is that injured cells induce the release of neurotrophic factors to trigger neurogenesis. Extracellular purine nucleotides exert multiple neurotrophic actions in the central nervous system mediated via activation of purinergic receptors. However, whether purinergics have a neurotrophic role in the olfactory neuroepithelium has not been investigated. Thus, we monitored the ATP-induced release of neuropeptide Y (NPY), a neuropeptide that increases neuroproliferation in the olfactory epithelium. To visualize NPY release, slices of olfactory epithelium from neonatal mice were cultured on nitrocellulose paper. Immunoassays of the nitrocellulose demonstrated NPY immunoreactivity in regions corresponding to the olfactory epithelium of the nasal cavity. One hour of exposure to exogenous ATP (100, 500 microM) significantly increased the number of olfactory epithelium slices that released NPY from 25% +/- 6% to 60% +/- 7% or 71% +/- 10% (P = 0.001). The purinergic receptor antagonists pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS; 25 microM) and suramin (100 microM) significantly reduced the number of olfactory epithelium slices exhibiting ATP-evoked NPY release to 18% +/- 11% (P = 0.004), indicating that NPY release is mediated by activation of purinergic receptors. Released NPY was quantified by enzyme and radioimmunoassays. Exogenous ATP or UTP significantly increased the amount of NPY released. Overall, this study demonstrates that purinergic receptor activation mediates the release of neurotrophic factor NPY in the olfactory epithelium and provides pharmacological targets to promote regeneration of damaged olfactory epithelium.
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Affiliation(s)
- Shami Kanekar
- Department of Physiology, University of Utah, Salt Lake City, Utah, USA
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Hassenklöver T, Kurtanska S, Bartoszek I, Junek S, Schild D, Manzini I. Nucleotide-induced Ca2+ signaling in sustentacular supporting cells of the olfactory epithelium. Glia 2009; 56:1614-24. [PMID: 18551628 DOI: 10.1002/glia.20714] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Extracellular purines and pyrimidines are important signaling molecules acting via purinergic cell-surface receptors in neurons, glia, and glia-like cells such as sustentacular supporting cells (SCs) of the olfactory epithelium (OE). Here, we thoroughly characterize ATP-induced responses in SCs of the OE using functional Ca2+ imaging. The initial ATP-induced increase of the intracellular Ca2+ concentration [Ca2+]i always occurred in the apical part of SCs and subsequently propagated toward the basal lamina, indicating the occurrence of purinergic receptors in the apical part of SCs. The mean propagation velocity of the Ca2+ signal within SCs was 17.10 +/- 1.02 microm/s. ATP evoked increases in [Ca2+]i in both the presence and absence of extracellular Ca2+. Depletion of the intracellular Ca2+ stores abolished the responses. This shows that the ATP-induced [Ca2+]i increases were in large part, if not entirely, due to the activation of G protein-coupled receptors followed by Ca2+ mobilization from intracellular stores, suggesting an involvement of P2Y receptors. The order of potency of the applied purinergic agonists was UTP > ATP > ATPgammaS (with all others being only weakly active or inactive). The ATP-induced [Ca2+]i increases could be reduced by the purinergic antagonists PPADS and RB2, but not by suramin. Our findings suggest that extracellular nucleotides in the OE activate SCs via P2Y2/P2Y4-like receptors and initiate a characteristic intraepithelial Ca2+ wave.
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Affiliation(s)
- Thomas Hassenklöver
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, Göttingen, Germany
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27
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Manzini I, Heermann S, Czesnik D, Brase C, Schild D, Rössler W. Presynaptic protein distribution and odour mapping in glomeruli of the olfactory bulb of Xenopus laevis tadpoles. Eur J Neurosci 2007; 26:925-34. [PMID: 17666078 DOI: 10.1111/j.1460-9568.2007.05731.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The sensory input layer in the olfactory bulb (OB) is typically organized into spheroidal aggregates of dense neuropil called glomeruli. This characteristic compartmentalization of the synaptic neuropil is a typical feature of primary olfactory centres in vertebrates and most advanced invertebrates. In the present work we mapped the location of presynaptic sites in glomeruli across the OB using antibodies to presynaptic vesicle proteins and presynaptic membrane proteins in combination with confocal microscopy. In addition the responses of glomeruli upon mucosal application of amino acid-odorants and forskolin were monitored using functional calcium imaging. We first describe the spatial distribution of glomeruli across the main olfactory bulb (MOB) in premetamorphic Xenopus laevis. Second, we show that the heterogeneous organization of glomeruli along the dorsoventral and mediolateral axes of the MOB is associated with a differential distribution of synaptic vesicle proteins. While antibodies to synaptophysin, syntaxin and SNAP-25 uniformly labelled glomeruli in the whole MOB, intense synaptotagmin staining was present only in glomeruli in the lateral, and to a lesser extent in the intermediate, part of the OB. Interestingly, amino acid-responsive glomeruli were always located in the lateral part of the OB, and glomeruli activated by mucosal forskolin application were exclusively located in the medial part of the OB. This correlation between odour mapping and presynaptic protein distribution is an additional hint on the existence of different subsystems within the main olfactory system in larval Xenopus laevis.
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Affiliation(s)
- Ivan Manzini
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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29
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Manzini I, Brase C, Chen TW, Schild D. Response profiles to amino acid odorants of olfactory glomeruli in larval Xenopus laevis. J Physiol 2007; 581:567-79. [PMID: 17347262 PMCID: PMC2075197 DOI: 10.1113/jphysiol.2007.130518] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glomeruli in the vertebrate olfactory bulb (OB) appear as anatomically discrete modules receiving direct input from the olfactory epithelium (OE) via axons of olfactory receptor neurons (ORNs). The response profiles with respect to amino acids (AAs) of a large number of ORNs in larval Xenopus laevis have been recently determined and analysed. Here we report on Ca(2+) imaging experiments in a nose-brain preparation of the same species at the same developmental stages. We recorded responses to AAs of glomeruli in the OB and determined the response profiles to AAs of individual glomeruli. We describe the general features of AA-responsive glomeruli and compare their response profiles to AAs with those of ORNs obtained in our previous study. A large number of past studies have focused either on odorant responses in the OE or on odorant-induced responses in the OB. However, a thorough comparison of odorant-induced responses of both stages, ORNs and glomeruli of the same species is as yet lacking. The glomerular response profiles reported herein markedly differ from the previously obtained response profiles of ORNs in that glomeruli clearly have narrower selectivity profiles than ORNs. We discuss possible explanations for the different selectivity profiles of glomeruli and ORNs in the context of the development of the olfactory map.
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Affiliation(s)
- Ivan Manzini
- Department of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
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30
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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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31
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Weiler E, Benali A. Olfactory epithelia differentially express neuronal markers. ACTA ACUST UNITED AC 2006; 34:217-40. [PMID: 16841165 DOI: 10.1007/s11068-005-8355-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 02/17/2006] [Accepted: 03/02/2006] [Indexed: 01/09/2023]
Abstract
All three olfactory epithelia, the olfactory epithelium proper (OE), the septal organ of Masera (SO), and the vomeronasal organ of Jacobson (VNO) originate from the olfactory placode. Here, their diverse neurochemical phenotypes were analyzed using the immunohistochemical expression pattern of different neuronal markers. The olfactory bulb (OB) served as neuronal control. Neuronal Nuclei Marker (NeuN) is neither expressed in sensory neurons in any of the three olfactory epithelia, nor in relay neurons (mitral/tufted cells) of the OB. However, OB interneurons (periglomerular/granule cells) labeled, as did supranuclear structures of VNO supporting cells and VNO glands. Protein Gene Product 9.5 (PGP9.5 = C-terminal ubiquitin hydrolase L1 = UCHL1) expression is exactly the opposite: all olfactory sensory neurons express PGP9.5 as do OB mitral/tufted cells but not interneurons. Neuron Specific Enolase (NSE) expression is highest in the most apically located OE and SO sensory neurons and patchy in VNO. In contrast, the cytoplasm of the most basally located neurons of OE and SO immunoreacted for Growth Associated Protein 43 (GAP-43/B50). In VNO neurons GAP-43 labeling is also nuclear. In the cytoplasm, Olfactory Marker Protein (OMP) is most intensely expressed in SO, followed by OE and least in VNO neurons; further, OMP is also expressed in the nucleus of basally located VNO neurons. OB mitral/tufted cells express OMP at low levels. Neurons closer to respiratory epithelium often expressed a higher level of neuronal markers, suggesting a role of those markers for neuronal protection against take-over. Within the VNO the neurons show clear apical-basal expression diversity, as they do for factors of the signal transduction cascade. Overall, expression patterns of the investigated neuronal markers suggest that OE and SO are more similar to each other than to VNO.
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Affiliation(s)
- Elke Weiler
- Department of Neurophysiology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
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