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Ngernsoungnern P, Rungsawang P, Janthaweera A, Duangsuwan P, Saowakon N, Sritangos P, Ngernsoungnern A. Ultrastructural study of neuronal cells and localization of ghrelin-like peptide and its receptor in the ganglia of the golden apple snail (Pomacea canaliculata). Tissue Cell 2024; 88:102348. [PMID: 38493758 DOI: 10.1016/j.tice.2024.102348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 03/02/2024] [Accepted: 03/04/2024] [Indexed: 03/19/2024]
Abstract
Pomacea canaliculata is an invasive snail species causing major problems in agriculture. The snail biology was then investigated. The main objective of the present study was to investigate the nervous system of the snail. The nervous system comprises pairs of cerebral, buccal, pedal, pleural, parietal ganglia and an unpaired visceral ganglion. Most neurons were concentrated at the periphery of the ganglia. The neurons were classified into four types: NR1, NR2, NR3, and NR4. The percentages of the NR3 and NR4 in the pleural and pedal ganglia were significantly higher than those of other ganglia. Ultrastructural study revealed that nuclei of all neuronal types exhibited mostly euchromatins. Many organelles including ribosomes and endoplasmic reticulum were found in their cytoplasm. However, various mitochondria were found in the NR2 and NR3. The immunohistochemistry revealed immunoreactivity of ghrelin-like peptide in the neurons of the cerebral, pleural and pedal ganglia. However, immunoreactivity of GHS-R1a-like peptide existed only in the neurons of the pleural and pedal ganglia. The present study is the first to demonstrate the existence of ghrelin-like peptide and its receptor in P. canaliculata nervous system.
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Affiliation(s)
- Piyada Ngernsoungnern
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Piyachat Rungsawang
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | | | - Pornsawan Duangsuwan
- Anatomy Program, Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
| | - Naruwan Saowakon
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Pishyaporn Sritangos
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Apichart Ngernsoungnern
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
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Young T, Gale SL, Ragg NLC, Sander SG, Burritt DJ, Benedict B, Le DV, Villas-Bôas SG, Alfaro AC. Metabolic Regulation of Copper Toxicity during Marine Mussel Embryogenesis. Metabolites 2023; 13:838. [PMID: 37512545 PMCID: PMC10385052 DOI: 10.3390/metabo13070838] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/19/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
The development of new tools for assessing the health of cultured shellfish larvae is crucial for aquaculture industries to develop and refine hatchery methodologies. We established a large-volume ecotoxicology/health stressor trial, exposing mussel (Perna canaliculus) embryos to copper in the presence of ethylenediaminetetraacetic acid (EDTA). GC/MS-based metabolomics was applied to identify potential biomarkers for monitoring embryonic/larval health and to characterise mechanisms of metal toxicity. Cellular viability, developmental abnormalities, larval behaviour, mortality, and a targeted analysis of proteins involved in the regulation of reactive oxygen species were simultaneously evaluated to provide a complementary framework for interpretative purposes and authenticate the metabolomics data. Trace metal analysis and speciation modelling verified EDTA as an effective copper chelator. Toxicity thresholds for P. canaliculus were low, with 10% developmental abnormalities in D-stage larvae being recorded upon exposure to 1.10 μg·L-1 bioavailable copper for 66 h. Sublethal levels of bioavailable copper (0.04 and 1.10 μg·L-1) caused coordinated fluctuations in metabolite profiles, which were dependent on development stage, treatment level, and exposure duration. Larvae appeared to successfully employ various mechanisms involving the biosynthesis of antioxidants and a restructuring of energy-related metabolism to alleviate the toxic effects of copper on cells and developing tissues. These results suggest that regulation of trace metal-induced toxicity is tightly linked with metabolism during the early ontogenic development of marine mussels. Lethal-level bioavailable copper (50.3 μg·L-1) caused severe metabolic dysregulation after 3 h of exposure, which worsened with time, substantially delayed embryonic development, induced critical oxidative damage, initiated the apoptotic pathway, and resulted in cell/organism death shortly after 18 h of exposure. Metabolite profiling is a useful approach to (1) assess the health status of marine invertebrate embryos and larvae, (2) detect early warning biomarkers for trace metal contamination, and (3) identify novel regulatory mechanisms of copper-induced toxicity.
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Affiliation(s)
- Tim Young
- Aquaculture Biotechnology Research Group, Department of Environmental Science, School of Science, Auckland University of Technology, Auckland 1010, New Zealand
- Centre for Biomedical and Chemical Sciences, School of Science, Auckland University of Technology, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | | | | | - Sylvia G. Sander
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9010, New Zealand
- Marine Mineral Resources Group, Research Division 4: Dynamics of the Ocean Floor, Magmatic and Hydrothermal Systems, GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany
| | - David J. Burritt
- Department of Botany, University of Otago, 464 Great King St, Dunedin 9016, New Zealand
| | - Billy Benedict
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9010, New Zealand
| | - Dung V. Le
- Aquaculture Biotechnology Research Group, Department of Environmental Science, School of Science, Auckland University of Technology, Auckland 1010, New Zealand
- Faculty of Fisheries, Vietnam National University of Agriculture, Hanoi 000084, Vietnam
| | - Silas G. Villas-Bôas
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Andrea C. Alfaro
- Aquaculture Biotechnology Research Group, Department of Environmental Science, School of Science, Auckland University of Technology, Auckland 1010, New Zealand
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Horváth R, Battonyai I, Maász G, Schmidt J, Fekete ZN, Elekes K. Chemical-neuroanatomical organization of peripheral sensory-efferent systems in the pond snail (Lymnaea stagnalis). Brain Struct Funct 2020; 225:2563-2575. [PMID: 32951073 PMCID: PMC7544616 DOI: 10.1007/s00429-020-02145-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022]
Abstract
Perception and processing of chemical cues are crucial for aquatic gastropods, for proper elaboration of adaptive behavior. The pond snail, Lymnaea stagnalis, is a model species of invertebrate neurobiology, in which peripheral sensory neurons with different morphology and transmitter content have partly been described, but we have little knowledge regarding their functional morphological organization, including their possible peripheral intercellular connections and networks. Therefore the aim of our study was to characterize the sensory system of the tentacles and the lip, as primary sensory regions, and the anterior foot of Lymnaea with special attention to the transmitter content of the sensory neurons, and their relationship to extrinsic elements of the central nervous system. Numerous bipolar sensory cells were demonstrated in the epithelial layer of the peripheral organs, displaying immunoreactivity to antibodies raised against tyrosine hydroxylase, histamine, glutamate and two molluscan type oligopeptides, FMRFamide and Mytilus inhibitory peptide. A subepithelial plexus was formed by extrinsic serotonin and FMRFamide immunoreactive fibers, whereas in deeper regions axon processess of different origin with various immunoreactivities formed networks, too. HPLC-MS assay confirmed the presence of the low molecular weight signal molecules in the three examined areas. Following double-labeling immunohistochemistry, close arrangements were observed, formed by sensory neurons and extrinsic serotonergic (and FMRFamidergic) fibers at axo-dendritic, axo-somatic and axo-axonic levels. Our results suggest the involvement of a much wider repertoire of signal molecules in peripheral sensory processes of Lymnaea, which can locally be modified by central input, hence influencing directly the responses to environmental cues.
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Affiliation(s)
- Réka Horváth
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary.
| | - Izabella Battonyai
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary
| | - Gábor Maász
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary
| | - János Schmidt
- Department of Analytical Biochemistry, Institute of Biochemistry and Medical Chemistry, University of Pécs, 7624, Pécs, Hungary
| | - Zsuzsanna N Fekete
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary
| | - Károly Elekes
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary
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Beach GA, Habib MR, El Hiani Y, Miller MW, Croll RP. Localization of keyhole limpet hemocyanin-like immunoreactivity in the nervous system of Biomphalaria alexandrina. J Neurosci Res 2019; 97:1469-1482. [PMID: 31379045 PMCID: PMC10401489 DOI: 10.1002/jnr.24497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 06/14/2019] [Accepted: 07/03/2019] [Indexed: 01/16/2023]
Abstract
Recent years have led to increased effort to describe and understand the peripheral nervous system and its influence on central mechanisms and behavior in gastropod molluscs. This study revealed that an antibody raised against keyhole limpet hemocyanin (KLH) cross-reacts with an antigen(s) found extensively in both the central and the peripheral nervous systems of Biomphalaria alexandrina. The results revealed KLH-like immunoreactive (LIR) neurons in the cerebral, pedal, buccal, left pleural, right parietal, and visceral ganglion within the CNS with fibers projecting throughout all the peripheral nerves. Numerous KLH-LIR peripheral sensory neurons located in the foot, lips, tentacles, mantle, esophagus, and penis exhibited a bipolar morphology with long tortuous dendrites. KLH-LIR cells were also present in the eye and statocyst, thus suggesting the labeling of multiple sensory modalities/cell types. KLH-LIR cells did not co-localize with tyrosine hydroxylase (TH)-LIR cells, which have previously been described in this and other gastropods. The results thus provide descriptions of thousands of peripheral sensory neurons, not previously described in detail. Future research should seek to pair sensory modalities with peripheral cell type and attempt to further elucidate the nature of KLH-like reactivity. These findings also emphasize the need for caution when analyzing results obtained through use of antibodies raised against haptens conjugated to carrier proteins, suggesting the need for stringent controls to help limit potential confounds caused by cross-reactivity. In addition, this study is the first to describe neuronal cross-reactivity with KLH in Biomphalaria, which could provide a substrate for host-parasite interactions with a parasitic trematode, Schistosoma.
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Affiliation(s)
- Griffin A Beach
- Department of Physiology & Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Mohamed R Habib
- Medical Malacology Laboratory, Theodor Bilharz Research Institute, Giza, Egypt
| | - Yassine El Hiani
- Department of Physiology & Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Mark W Miller
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico.,Department of Anatomy & Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Roger P Croll
- Department of Physiology & Biophysics, Dalhousie University, Halifax, NS, Canada
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5
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Abstract
Gastropod diversity is substantial in marine and freshwater habitats, and many aquatic slugs and snails use olfactory cues to guide their navigation behaviour. Examples include finding prey or avoiding predators based on kairomones, or finding potential mates using pheromones. Here, I review the diversity of navigational behaviours studied across the major aquatic taxa of gastropods. I then synthesize evidence for the different theoretical navigation strategies the animals may use. It is likely that gastropods regularly use either chemotaxis or odour-gated rheotaxis (or both) during olfactory-based navigation. Finally, I collate the patchwork of research conducted on relevant proximate mechanisms that could produce navigation behaviours. Although the tractability of several gastropod species for neurophysiological experimentation has generated some valuable insight into how turning behaviour is triggered by contact chemoreception, there remain many substantial gaps in our understanding for how navigation relative to more distant odour sources is controlled in gastropods. These gaps include little information on the chemoreceptors and mechanoreceptors (for detecting flow) found in the peripheral nervous system and the central (or peripheral) processing circuits that integrate that sensory input. In contrast, past studies do provide information on motor neurons that control the effectors that produce crawling (both forward locomotion and turning). Thus, there is plenty of scope for further research on olfactory-based navigation, exploiting the tractability of gastropods for neuroethology to better understand how the nervous system processes chemosensory input to generate movement towards or away from distant odour sources.
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Affiliation(s)
- Russell C Wyeth
- Biology Department, St Francis Xavier University, 2321 Notre Dame Avenue, Antigonish, NS, Canada B2G 2W5
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Nacsa K, Elekes K, Serfőző Z. Ultrastructural localization of NADPH diaphorase and nitric oxide synthase in the neuropils of the snail CNS. Micron 2015; 75:58-66. [DOI: 10.1016/j.micron.2015.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 12/15/2022]
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7
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Wilkie IC, Barbaglio A, Carnevali MDC. The elusive role of L-glutamate as an echinoderm neurotransmitter: evidence for its involvement in the control of crinoid arm muscles. ZOOLOGY 2012; 116:1-8. [PMID: 23141629 DOI: 10.1016/j.zool.2012.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 05/21/2012] [Accepted: 06/12/2012] [Indexed: 11/28/2022]
Abstract
Although l-glutamate is the most widespread excitatory neurotransmitter in vertebrate and invertebrate nervous systems, there is only sparse evidence that it has this role in echinoderms. Following our previous finding that l-glutamate is widely distributed in the arms of the featherstar (crinoid echinoderm) Antedon mediterranea and initiates arm autotomy (defensive detachment), we now provide evidence of glutamatergic involvement in the control of the arm muscles of the same species using immunocytochemical and physiological methods. Immunofluorescence and immunoenzymatic techniques, which employed the same polyclonal antibody against l-glutamate conjugated to glutaraldehyde, revealed a high level of glutamate-like reactivity in the brachial muscles. By recording the mechanical responses of isolated arm pieces, we found that l-glutamate, l-aspartate and elevated [K(+)](o) induced rhythmic muscle contractions, while glycine, γ-aminobutyric acid, adrenaline and acetylcholine had either no, or no consistent, effect. The frequency and duration of the dominant component of the rhythmic contractions indicated that these may be responsible for the rhythmic activity of the arms that occurs during swimming and after autotomy. We conclude that it is highly likely that l-glutamate has at least a neuromodulatory role in the neural pathways controlling the brachial muscles of A. mediterranea.
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Affiliation(s)
- Iain C Wilkie
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, United Kingdom.
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8
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Balog G, Voronezhskaya EE, Hiripi L, Elekes K. Organization of the serotonergic innervation of the feeding (buccal) musculature during the maturation of the pond snail Lymnaea stagnalis: a morphological and biochemical study. J Comp Neurol 2012; 520:315-29. [PMID: 21674495 DOI: 10.1002/cne.22693] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The serotonergic innervation of the buccal musculature responsible for feeding (radula protraction) was investigated during the maturation of the pond snail, Lymnaea stagnalis L., applying light and electron microscopic immunohistochemistry and biochemical approaches. According to epifluorescence and laser confocal microscopy, the first 5-HT-like-immunoreactive (5-HTLIR) processes appeared on the surface of the musculature at the postmetamorphic E80% embryonic stage. Until hatching, the innervation continued to increase in density, showing axon arborizations with projections into the deeper muscle levels. An adult-like pattern of 5-HTLIR innervation appeared at P2-P3 juvenile stages. At the ultrastructural level, close (16-20 nm) but mostly unspecialized neuromuscular contacts were formed by both unlabeled and 5-HTLIR axon profiles from the E80% embryonic stage. Labeled processes were also found located relatively far from the muscle cells. An HPLC assay showed a gradual increase of the 5-HT level in the buccal mass during development. The buccal mass was characterized by a single-component high-affinity 5-HT uptake system, and 5-HT release could be evoked by 100 mM K(+) and blocked in Ca(2+) -free medium. It is suggested that 5-HT plays a wide modulatory role in the peripheral feeding system and is also involved in the functional maturation of the muscle system.
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Affiliation(s)
- Gábor Balog
- Department of Experimental Zoology, Balaton Limnological Research Institute, Hungarian Academy of Sciences, H-8237 Tihany, Hungary
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Wyeth RC, Croll RP. Peripheral sensory cells in the cephalic sensory organs of Lymnaea stagnalis. J Comp Neurol 2011; 519:1894-913. [PMID: 21452209 DOI: 10.1002/cne.22607] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The peripheral nervous system in gastropods plays a key role in the neural control of behaviors, but is poorly studied in comparison with the central nervous system. Peripheral sensory neurons, although known to be widespread, have been studied in a patchwork fashion across several species, with no comprehensive treatment in any one species. We attempted to remedy this limitation by cataloging peripheral sensory cells in the cephalic sensory organs of Lymnaea stagnalis employing backfills, vital stains, histochemistry, and immunohistochemistry. By using at least two independent methods to corroborate observations, we mapped four different cell types. We have found two different populations of bipolar sensory cells that appear to contain catecholamines(s) and histamine, respectively. Each cell had a peripheral soma, an epithelial process bearing cilia, and a second process projecting to the central nervous system. We also found evidence for two populations of nitric oxide-producing sensory cells, one bipolar, probably projecting centrally, and the second unipolar, with only a single epithelial process and no axon. The various cell types are presumably either mechanosensory or chemosensory, but the complexity of their distributions does not allow formation of hypotheses regarding modality. In addition, our observations indicate that yet more peripheral sensory cell types are present in the cephalic sensory organs of L. stagnalis. These results are an important step toward linking sensory cell morphology to modality. Moreover, our observations emphasize the size of the peripheral nervous system in gastropods, and we suggest that greater emphasis be placed on understanding its role in gastropod neuroethology.
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Affiliation(s)
- Russell C Wyeth
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada.
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Wilkie IC, Barbaglio A, Maclaren WM, Carnevali MDC. Physiological and immunocytochemical evidence that glutamatergic neurotransmission is involved in the activation of arm autotomy in the featherstar Antedon mediterranea (Echinodermata: Crinoidea). ACTA ACUST UNITED AC 2010; 213:2104-15. [PMID: 20511525 DOI: 10.1242/jeb.039578] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The crinoid echinoderm Antedon mediterranea autotomises its arms at specialised skeletal joints known as syzygies that occur at regular intervals along the length of each arm. Detachment is achieved through the nervously mediated destabilisation of ligament fibres at a particular syzygy. The aim of this investigation was to identify neurotransmitters that are involved in the autotomy response. Physiological experiments were conducted on isolated preparations of syzygial joints, which can be induced to undergo autotomy-like fracture by applying stimulatory agents such as elevated [K(+)](o). Initial experiments with elevated [K(+)](o) showed that the autotomy threshold (the minimum amount of stimulation required to provoke autotomy) is lowest in syzygies at the arm base and rises distally. Of a range of neurotransmitter agonists tested, only l-glutamate invoked syzygial destabilisation, as did its analogues l-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and kainate, but not l-(+)-2-amino-4-phosphonobutyrate (l-AP4) or N-methyl-d-aspartate (NMDA). The implication that l-glutamate stimulates syzygial fracture through AMPA/kainate-like receptors was supported by the finding that the action of l-glutamate was inhibited by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Acetylcholine depressed the response of syzygial preparations to l-glutamate, suggesting a possible mechanism by which the autotomy threshold could be varied constitutively and facultatively. An immunocytochemical method employing a polyclonal antibody against l-glutamate conjugated to glutaraldehyde revealed l-glutamate-like immunoreactivity in all components of the putative neural pathway controlling the autotomy reflex, including the epidermis, brachial nerve, syzygial nerves and cellular elements close to the syzygial ligaments. We conclude that it is highly probable that l-glutamate acts as an excitatory neurotransmitter in the activation of arm autotomy in A. mediterranea.
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Affiliation(s)
- I C Wilkie
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
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Hatakeyama D, Mita K, Kobayashi S, Sadamoto H, Fujito Y, Hiripi L, Elekes K, Ito E. Glutamate transporters in the central nervous system of a pond snail. J Neurosci Res 2010; 88:1374-86. [PMID: 19937812 DOI: 10.1002/jnr.22296] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous studies on glutamate (GLU) and its receptors in the pond snail Lymnaea stagnalis have suggested that GLU functions as a neurotransmitter in various behaviors, particularly for generation of feeding rhythm. The uptake mechanism of GLU is not yet known in Lymnaea. In the present study, we characterized the GLU transporters and examined their functions in the feeding circuits of the central nervous system (CNS) in Lymnaea. First, measurement of the accumulation of (3)H-labeled GLU revealed the presence of GLU transport systems in the Lymnaea CNS. The highest accumulation rate was observed in the buccal ganglia, supporting the involvement of GLU transport systems in feeding behavior. Second, we cloned two types of GLU transporters from the Lymnaea CNS, the excitatory amino acid transporter (LymEAAT) and the vesicular GLU transporter (LymVGLUT). When we compared their amino acid sequences with those of mammalian EAATs and VGLUTs, we found that the functional domains of both types are well conserved. Third, in situ hybridization revealed that the mRNAs of LymEAAT and LymVGLUT are localized in large populations of nerve cells, including the major feeding motoneurons in the buccal ganglia. Finally, we inhibited LymEAAT and found that changes in the firing patterns of the feeding motoneurons that have GLUergic input were similar to those obtained following stimulation with GLU. Our results confirmed the presence of GLU uptake systems in the Lymnaea CNS and showed that LymEAAT is required for proper rhythm generation, particularly for generation of the feeding rhythm.
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Affiliation(s)
- Dai Hatakeyama
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Japan
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12
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Delayed intrinsic activation of an NMDA-independent CaM-kinase II in a critical time window is necessary for late consolidation of an associative memory. J Neurosci 2010; 30:56-63. [PMID: 20053887 DOI: 10.1523/jneurosci.2577-09.2010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Calcium/calmodulin-dependent kinases (CaM-kinases) are central to various forms of long-term memory (LTM) in a number of evolutionarily diverse organisms. However, it is still largely unknown what contributions specific CaM-kinases make to different phases of the same specific type of memory, such as acquisition, or early, intermediate, and late consolidation of associative LTM after classical conditioning. Here, we investigated the involvement of CaM-kinase II (CaMKII) in different phases of associative LTM induced by single-trial reward classical conditioning in Lymnaea, a well established invertebrate experimental system for studying molecular mechanisms of learning and memory. First, by using a general CaM-kinase inhibitor, KN-62, we found that CaM-kinase activation was necessary for acquisition and late consolidation, but not early or intermediate consolidation or retrieval of LTM. Then, we used Western blot-based phosphorylation assays and treatment with CaMKIINtide to identify CaMKII as the main CaM-kinase, the intrinsic activation of which, in a critical time window ( approximately 24 h after learning), is central to late consolidation of LTM. Additionally, using MK-801 and CaMKIINtide we found that acquisition was dependent on both NMDA receptor and CaMKII activation. However, unlike acquisition, CaMKII-dependent late memory consolidation does not require the activation of NMDA receptors. Our new findings support the notion that even apparently stable memory traces may undergo further molecular changes and identify NMDA-independent intrinsic activation of CaMKII as a mechanism underlying this "lingering consolidation." This process may facilitate the preservation of LTM in the face of protein turnover or active molecular processes that underlie forgetting.
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Report on a symposium on Invertebrate Models of Behavior and Circuit Plasticity. INVERTEBRATE NEUROSCIENCE 2009; 9:101-9. [PMID: 19834753 DOI: 10.1007/s10158-009-0093-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 10/06/2009] [Indexed: 10/20/2022]
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Matsuo R, Kobayashi S, Watanabe S, Namiki S, Iinuma S, Sakamoto H, Hirose K, Ito E. Glutamatergic neurotransmission in the procerebrum (Olfactory center) of a terrestrial mollusk. J Neurosci Res 2009; 87:3011-23. [DOI: 10.1002/jnr.22130] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Megalou EV, Brandon CJ, Frost WN. Evidence that the swim afferent neurons of tritonia diomedea are glutamatergic. THE BIOLOGICAL BULLETIN 2009; 216:103-112. [PMID: 19366921 PMCID: PMC3073080 DOI: 10.1086/bblv216n2p103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The escape swim response of the marine mollusc Tritonia diomedea is a well-established model system for studies of the neural basis of behavior. Although the swim neural network is reasonably well understood, little is known about the transmitters used by its constituent neurons. In the present study, we provide immunocytochemical and electrophysiological evidence that the S-cells, the afferent neurons that detect aversive skin stimuli and in turn trigger Tritonia's escape swim response, use glutamate as their transmitter. First, immunolabeling revealed that S-cell somata contain elevated levels of glutamate compared to most other neurons in the Tritonia brain, consistent with findings from glutamatergic neurons in many species. Second, pressure-applied puffs of glutamate produced the same excitatory response in the target neurons of the S-cells as the naturally released S-cell transmitter itself. Third, the glutamate receptor antagonist CNQX completely blocked S-cell synaptic connections. These findings support glutamate as a transmitter used by the S-cells, and will facilitate studies using this model system to explore a variety of issues related to the neural basis of behavior.
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Affiliation(s)
- E V Megalou
- Department of Cell Biology and Anatomy, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064, USA
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Moccia F, Di Cristo C, Winlow W, Di Cosmo A. GABA(A)- and AMPA-like receptors modulate the activity of an identified neuron within the central pattern generator of the pond snail Lymnaea stagnalis. INVERTEBRATE NEUROSCIENCE 2009; 9:29-41. [PMID: 19214610 DOI: 10.1007/s10158-009-0086-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 01/06/2009] [Indexed: 11/28/2022]
Abstract
To examine the neurochemistry underlying the firing of the RPeD1 neuron in the respiratory central pattern generator of the pond snail, Lymnaea stagnalis, we examined electrophysiologically and pharmacologically either "active" or "silent" preparations by intracellular recording and pharmacology. GABA inhibited electrical firing by hyperpolarizing RPeD1, while picrotoxin, an antagonist of GABA(A) receptors, excited silent cells and reversed GABA-induced inhibition. Action potential activity was terminated by 1 mM glutamate (Glu) while silent cells were depolarized by the GluR agonists, AMPA, and NMDA. Kainate exerted a complex triphasic effect on membrane potential. However, only bath application of AMPA desensitized the firing. These data indicate that GABA inhibits RPeD1 via activation of GABA(A) receptors, while Glu stimulates the neuron by activating AMPA-sensitive GluRs.
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Affiliation(s)
- Francesco Moccia
- Department of Structural and Functional Biology, University of Naples "Federico II" Complesso Universitario, Monte S. Angelo, viale Cinthia, 80126 Naples, Italy
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