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Yuste R. Breaking the neural code of a cnidarian: Learning principles of neuroscience from the "vulgar" Hydra. Curr Opin Neurobiol 2024; 86:102869. [PMID: 38552547 DOI: 10.1016/j.conb.2024.102869] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/04/2024] [Accepted: 03/07/2024] [Indexed: 06/11/2024]
Abstract
The cnidarian Hydra vulgaris is a small polyp with a nervous system of few hundred neurons belonging to a dozen cell types, organized in two nerve nets without cephalization or ganglia. Using this simple neural "chassis", Hydra can maintain a stable repertoire of behaviors, even performing complex fixed-action patterns, such as somersaulting and feeding. The ability to image the activity of Hydra's entire neural and muscle tissue has revealed that Hydra's nerve nets are divided into coactive ensembles of neurons, associated with specific movements. These ensembles can be activated by neuropeptides and interact using cross-inhibition circuits and implement integrate-to-threshold algorithms. In addition, Hydra's nervous system can self-assemble from dissociated cells in a stepwise modular architecture. Studies of Hydra and other cnidarians could enable the systematic deciphering of the neural basis of its behavior and help provide perspective on basic principles of neuroscience.
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Affiliation(s)
- Rafael Yuste
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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2
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Keramidioti A, Schneid S, Busse C, Cramer von Laue C, Bertulat B, Salvenmoser W, Hess M, Alexandrova O, Glauber KM, Steele RE, Hobmayer B, Holstein TW, David CN. A new look at the architecture and dynamics of the Hydra nerve net. eLife 2024; 12:RP87330. [PMID: 38407174 PMCID: PMC10942621 DOI: 10.7554/elife.87330] [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] [Indexed: 02/27/2024] Open
Abstract
The Hydra nervous system is the paradigm of a 'simple nerve net'. Nerve cells in Hydra, as in many cnidarian polyps, are organized in a nerve net extending throughout the body column. This nerve net is required for control of spontaneous behavior: elimination of nerve cells leads to polyps that do not move and are incapable of capturing and ingesting prey (Campbell, 1976). We have re-examined the structure of the Hydra nerve net by immunostaining fixed polyps with a novel antibody that stains all nerve cells in Hydra. Confocal imaging shows that there are two distinct nerve nets, one in the ectoderm and one in the endoderm, with the unexpected absence of nerve cells in the endoderm of the tentacles. The nerve nets in the ectoderm and endoderm do not contact each other. High-resolution TEM (transmission electron microscopy) and serial block face SEM (scanning electron microscopy) show that the nerve nets consist of bundles of parallel overlapping neurites. Results from transgenic lines show that neurite bundles include different neural circuits and hence that neurites in bundles require circuit-specific recognition. Nerve cell-specific innexins indicate that gap junctions can provide this specificity. The occurrence of bundles of neurites supports a model for continuous growth and differentiation of the nerve net by lateral addition of new nerve cells to the existing net. This model was confirmed by tracking newly differentiated nerve cells.
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Affiliation(s)
- Athina Keramidioti
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Sandra Schneid
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Christina Busse
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | | | - Bianca Bertulat
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Willi Salvenmoser
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Martin Hess
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Olga Alexandrova
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Kristine M Glauber
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Robert E Steele
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Bert Hobmayer
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Thomas W Holstein
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Charles N David
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
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3
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Tommasini G, De Simone M, Santillo S, Dufil G, Iencharelli M, Mantione D, Stavrinidou E, Tino A, Tortiglione C. In vivo neuromodulation of animal behavior with organic semiconducting oligomers. SCIENCE ADVANCES 2023; 9:eadi5488. [PMID: 37851802 PMCID: PMC10584338 DOI: 10.1126/sciadv.adi5488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 09/08/2023] [Indexed: 10/20/2023]
Abstract
Modulating neural activity with electrical or chemical stimulus can be used for fundamental and applied research. Typically, neuronal stimulation is performed with intracellular and extracellular electrodes that deliver brief electrical pulses to neurons. However, alternative wireless methodologies based on functional materials may allow clinical translation of technologies to modulate neuronal function. Here, we show that the organic semiconducting oligomer 4-[2-{2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophen-3-yl}ethoxy]butane-1-sulfonate (ETE-S) induces precise behaviors in the small invertebrate Hydra, which were dissected through pharmacological and electrophysiological approaches. ETE-S-induced behavioral response relies on the presence of head neurons and calcium ions and is prevented by drugs targeting ionotropic channels and muscle contraction. Moreover, ETE-S affects Hydra's electrical activity enhancing the contraction burst frequency. The unexpected neuromodulatory function played by this conjugated oligomer on a simple nerve net opens intriguing research possibilities on fundamental chemical and physical phenomena behind organic bioelectronic interfaces for neuromodulation and on alternative methods that could catalyze a wide expansion of this rising technology for clinical applications.
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Affiliation(s)
- Giuseppina Tommasini
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Mariarosaria De Simone
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Silvia Santillo
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Gwennaël Dufil
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrkoping, Sweden
| | - Marika Iencharelli
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Daniele Mantione
- POLYMAT University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain; IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Eleni Stavrinidou
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrkoping, Sweden
| | - Angela Tino
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Claudia Tortiglione
- Istituto di Scienze Applicate e Sistemi Intelligenti “E. Caianiello”, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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4
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Yamamoto W, Yuste R. Peptide-driven control of somersaulting in Hydra vulgaris. Curr Biol 2023; 33:1893-1905.e4. [PMID: 37040768 DOI: 10.1016/j.cub.2023.03.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/09/2023] [Accepted: 03/16/2023] [Indexed: 04/13/2023]
Abstract
The cnidarian Hydra vulgaris has a simple nervous system with a few hundred neurons in distributed networks. Yet Hydra can perform somersaults, a complex acrobatic locomotion. To understand the neural mechanisms of somersaulting we used calcium imaging and found that rhythmical potential 1 (RP1) neurons activate before somersaulting. Decreasing RP1 activity or ablating RP1 neurons reduced somersaulting, while two-photon activation of RP1 neurons induced somersaulting. Hym-248, a peptide synthesized by RP1 cells, selectively generated somersaulting. We conclude that RP1 activity, via release of Hym-248, is necessary and sufficient for somersaulting. We propose a circuit model to explain the sequential unfolding of this locomotion, using integrate-to-threshold decision making and cross-inhibition. Our work demonstrates that peptide-based signaling is used by simple nervous systems to generate behavioral fixed action patterns.
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Affiliation(s)
- Wataru Yamamoto
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Rafael Yuste
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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5
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Whole-Body Imaging of Neural and Muscle Activity during Behavior in Hydra vulgaris: Effect of Osmolarity on Contraction Bursts. eNeuro 2020; 7:ENEURO.0539-19.2020. [PMID: 32699071 PMCID: PMC7452734 DOI: 10.1523/eneuro.0539-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/28/2020] [Accepted: 05/11/2020] [Indexed: 11/21/2022] Open
Abstract
The neural code relates the activity of the nervous system to the activity of the muscles to the generation of behavior. To decipher it, it would be ideal to comprehensively measure the activity of the entire nervous system and musculature in a behaving animal. As a step in this direction, we used the cnidarian Hydra vulgaris to explore how physiological and environmental conditions alter simple contractile behavior and its accompanying neural and muscle activity. We used whole-body calcium imaging of neurons and muscle cells and studied the effect of temperature, media osmolarity, nutritional state, and body size on contractile behavior. In mounted Hydra preparations, changes in temperature, nutrition state, or body size did not have a major effect on neural or muscle activity, or on contractile behavior. But changes in media osmolarity systematically altered contractile behavior and foot detachments, increasing their frequency in hypo-osmolar media solutions and decreasing it in hyperosmolar media. Similar effects were seen in ectodermal, but not in endodermal muscle. Osmolarity also bidirectionally changed the activity of contraction burst (CB) neurons, but did not affect the network of rhythmic potential (RP) neurons in the ectoderm. These findings show osmolarity-dependent changes in the activity of CB neurons and ectodermal muscle, consistent with the hypothesis that CB neurons respond to media hypo-osmolarity, activating ectodermal muscle to generate CBs. This dedicated reflex could serve as an excretory system to prevent osmotic injury. This work demonstrates the feasibility of studying an entire neuronal and muscle activity in a behaving animal.
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Szymanski JR, Yuste R. Mapping the Whole-Body Muscle Activity of Hydra vulgaris. Curr Biol 2019; 29:1807-1817.e3. [PMID: 31130460 DOI: 10.1016/j.cub.2019.05.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/12/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022]
Abstract
Hydra is a cnidarian polyp with an anatomically simple neuromuscular system that can offer evolutionary insights on the functional design of animal body plans. Using calcium imaging to map the activity of the entire epitheliomuscular system of behaving Hydra, we find seven basic spatiotemporal patterns of muscle activity. Patterns include global and local activation events with widely varying kinetics of initiation and wave-like propagation. The orthogonally oriented endodermal and ectodermal muscle fibers are jointly activated during longitudinal contractions. Individual epitheliomuscular cells can participate in multiple patterns, even with very different kinetics. This cellular multifunctionality could enable the structurally simple epitheliomuscular tissue of basal metazoans to implement a diverse behavioral output.
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Affiliation(s)
- John R Szymanski
- Neurotechnology Center, Department Biological Sciences, Columbia University, New York, NY 10027, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA.
| | - Rafael Yuste
- Neurotechnology Center, Department Biological Sciences, Columbia University, New York, NY 10027, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA
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7
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Badhiwala KN, Gonzales DL, Vercosa DG, Avants BW, Robinson JT. Microfluidics for electrophysiology, imaging, and behavioral analysis of Hydra. LAB ON A CHIP 2018; 18:2523-2539. [PMID: 29987278 DOI: 10.1039/c8lc00475g] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The nervous system of the cnidarian Hydra vulgaris exhibits remarkable regenerative abilities. When cut in two, the bisected tissue reorganizes into fully behaving animals in approximately 48 hours. Furthermore, new animals can reform from aggregates of dissociated cells. Understanding how behaviors are coordinated by this highly plastic nervous system could reveal basic principles of neural circuit dynamics underlying behaviors. However, Hydra's deformable and contractile body makes it difficult to manipulate the local environment while recording neural activity. Here, we present the first microfluidic technologies capable of simultaneous electrical, chemical, and optical interrogation of these soft, deformable organisms. Specifically, we demonstrate devices that can immobilize Hydra for hours-long simultaneous electrical and optical recording, and chemical stimulation of behaviors revealing neural activity during muscle contraction. We further demonstrate quantitative locomotive and behavioral tracking made possible by confining the animal to quasi-two-dimensional micro-arenas. Together, these proof-of-concept devices show that microfluidics provide a platform for scalable, quantitative cnidarian neurobiology. The experiments enabled by this technology may help reveal how highly plastic networks of neurons provide robust control of animal behavior.
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Affiliation(s)
- Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
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8
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Petralia RS, Wang YX, Mattson MP, Yao PJ. Invaginating Presynaptic Terminals in Neuromuscular Junctions, Photoreceptor Terminals, and Other Synapses of Animals. Neuromolecular Med 2017; 19:193-240. [PMID: 28612182 PMCID: PMC6518423 DOI: 10.1007/s12017-017-8445-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Typically, presynaptic terminals form a synapse directly on the surface of postsynaptic processes such as dendrite shafts and spines. However, some presynaptic terminals invaginate-entirely or partially-into postsynaptic processes. We survey these invaginating presynaptic terminals in all animals and describe several examples from the central nervous system, including giant fiber systems in invertebrates, and cup-shaped spines, electroreceptor synapses, and some specialized auditory and vestibular nerve terminals in vertebrates. We then examine mechanoreceptors and photoreceptors, concentrating on the complex of pre- and postsynaptic processes found in basal invaginations of the cell. We discuss in detail the role of vertebrate invaginating horizontal cell processes in both chemical and electrical feedback mechanisms. We also discuss the common presence of indenting or invaginating terminals in neuromuscular junctions on muscles of most kinds of animals, and especially discuss those of Drosophila and vertebrates. Finally, we consider broad questions about the advantages of possessing invaginating presynaptic terminals and describe some effects of aging and disease, especially on neuromuscular junctions. We suggest that the invagination is a mechanism that can enhance both chemical and electrical interactions at the synapse.
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Affiliation(s)
- Ronald S Petralia
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA.
| | - Ya-Xian Wang
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
| | - Pamela J Yao
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
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9
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Non-overlapping Neural Networks in Hydra vulgaris. Curr Biol 2017; 27:1085-1097. [PMID: 28366745 DOI: 10.1016/j.cub.2017.02.049] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/08/2016] [Accepted: 02/20/2017] [Indexed: 11/23/2022]
Abstract
To understand the emergent properties of neural circuits, it would be ideal to record the activity of every neuron in a behaving animal and decode how it relates to behavior. We have achieved this with the cnidarian Hydra vulgaris, using calcium imaging of genetically engineered animals to measure the activity of essentially all of its neurons. Although the nervous system of Hydra is traditionally described as a simple nerve net, we surprisingly find instead a series of functional networks that are anatomically non-overlapping and are associated with specific behaviors. Three major functional networks extend through the entire animal and are activated selectively during longitudinal contractions, elongations in response to light, and radial contractions, whereas an additional network is located near the hypostome and is active during nodding. These results demonstrate the functional sophistication of apparently simple nerve nets, and the potential of Hydra and other basal metazoans as a model system for neural circuit studies.
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10
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Tortiglione C, Antognazza MR, Tino A, Bossio C, Marchesano V, Bauduin A, Zangoli M, Morata SV, Lanzani G. Semiconducting polymers are light nanotransducers in eyeless animals. SCIENCE ADVANCES 2017; 3:e1601699. [PMID: 28138549 PMCID: PMC5266477 DOI: 10.1126/sciadv.1601699] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/08/2016] [Indexed: 05/17/2023]
Abstract
Current implant technology uses electrical signals at the electrode-neural interface. This rather invasive approach presents important issues in terms of performance, tolerability, and overall safety of the implants. Inducing light sensitivity in living organisms is an alternative method that provides groundbreaking opportunities in neuroscience. Optogenetics is a spectacular demonstration of this, yet is limited by the viral transfection of exogenous genetic material. We propose a nongenetic approach toward light control of biological functions in living animals. We show that nanoparticles based on poly(3-hexylthiophene) can be internalized in eyeless freshwater polyps and are fully biocompatible. Under light, the nanoparticles modify the light response of the animals, at two different levels: (i) they enhance the contraction events of the animal body, and (ii) they change the transcriptional activation of the opsin3-like gene. This suggests the establishment of a seamless and biomimetic interface between the living organism and the polymer nanoparticles that behave as light nanotransducers, coping with or amplifying the function of primitive photoreceptors.
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Affiliation(s)
- Claudia Tortiglione
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Maria Rosa Antognazza
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Angela Tino
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Caterina Bossio
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Valentina Marchesano
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Antonella Bauduin
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Mattia Zangoli
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy
| | - Susana Vaquero Morata
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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Bosch TCG, Klimovich A, Domazet-Lošo T, Gründer S, Holstein TW, Jékely G, Miller DJ, Murillo-Rincon AP, Rentzsch F, Richards GS, Schröder K, Technau U, Yuste R. Back to the Basics: Cnidarians Start to Fire. Trends Neurosci 2016; 40:92-105. [PMID: 28041633 DOI: 10.1016/j.tins.2016.11.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022]
Abstract
The nervous systems of cnidarians, pre-bilaterian animals that diverged close to the base of the metazoan radiation, are structurally simple and thus have great potential to reveal fundamental principles of neural circuits. Unfortunately, cnidarians have thus far been relatively intractable to electrophysiological and genetic techniques and consequently have been largely passed over by neurobiologists. However, recent advances in molecular and imaging methods are fueling a renaissance of interest in and research into cnidarians nervous systems. Here, we review current knowledge on the nervous systems of cnidarian species and propose that researchers should seize this opportunity and undertake the study of members of this phylum as strategic experimental systems with great basic and translational relevance for neuroscience.
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Affiliation(s)
| | | | - Tomislav Domazet-Lošo
- Ruđer Bošković Institute, Zagreb, Croatia; Catholic University of Croatia, Zagreb, Croatia
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Germany
| | | | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - David J Miller
- ARC Centre of Excellence for Coral Reef Studies, Townsville, Australia
| | | | - Fabian Rentzsch
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway
| | - Gemma S Richards
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway; University of Queensland, Brisbane, Australia
| | | | | | - Rafael Yuste
- Neurotechnology Center, Columbia University, New York, NY, USA.
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12
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Guertin S, Kass-Simon G. Extraocular spectral photosensitivity in the tentacles of Hydra vulgaris. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:163-70. [PMID: 25724097 DOI: 10.1016/j.cbpa.2015.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/18/2015] [Accepted: 02/19/2015] [Indexed: 10/23/2022]
Abstract
Previous electrophysiological studies on the cnidarian Hydra vulgaris have shown that hydra have a highly developed and specific photoresponse despite their lack of any structure recognizable as a traditional photoreceptor. In an effort to identify the site of hydra's photoreceptors, we recorded extracellularly from single excised tentacles and from ablated hypostomes lacking tentacles in absolute darkness and during exposure to light of various wavelengths. During recording, after an initial period of absolute darkness, tentacles or hypostomes were exposed to light from 450nm to 600nm, red, and white light. Exposure to light caused a change in the pattern and frequency of impulses in the tentacles that varied with color. The number of large tentacle pulses (TPs) increased at 550 and 600nm relative to darkness, whereas the number of small tentacle pulses (STPs) tended to decrease in 500nm light. Impulse frequency was significantly different among the different wavelengths. In addition to bursts of tentacle contraction pulses, long trains of pulses were observed. A change in lighting caused a switch from bursting to trains or vice versa. In contrast to excised tentacles, no change in electrical activity was seen in ablated hypostomes at any of the wavelengths relative to each other or relative to darkness. These results indicate that isolated tentacles can distinguish among and respond to various colors across the visible spectrum and suggest that electromagnetic information is transmitted from the tentacles to the hypostome where it may be integrated by the hypostomal nervous system, ultimately contributing to hydra's photoreceptive behavior.
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Affiliation(s)
- S Guertin
- University of Rhode Island, Interdisciplinary Neurosciences Program, United States
| | - G Kass-Simon
- University of Rhode Island, Interdisciplinary Neurosciences Program, United States; University of Rhode Island, Department of Biological Sciences, United States
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13
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Takaku Y, Hwang JS, Wolf A, Böttger A, Shimizu H, David CN, Gojobori T. Innexin gap junctions in nerve cells coordinate spontaneous contractile behavior in Hydra polyps. Sci Rep 2014; 4:3573. [PMID: 24394722 PMCID: PMC3882753 DOI: 10.1038/srep03573] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/04/2013] [Indexed: 01/09/2023] Open
Abstract
Nerve cells and spontaneous coordinated behavior first appeared near the base of animal evolution in the common ancestor of cnidarians and bilaterians. Experiments on the cnidarian Hydra have demonstrated that nerve cells are essential for this behavior, although nerve cells in Hydra are organized in a diffuse network and do not form ganglia. Here we show that the gap junction protein innexin-2 is expressed in a small group of nerve cells in the lower body column of Hydra and that an anti-innexin-2 antibody binds to gap junctions in the same region. Treatment of live animals with innexin-2 antibody eliminates gap junction staining and reduces spontaneous body column contractions. We conclude that a small subset of nerve cells, connected by gap junctions and capable of synchronous firing, act as a pacemaker to coordinate the contraction of the body column in the absence of ganglia.
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Affiliation(s)
- Yasuharu Takaku
- Hamamatsu University School of Medicine, Department of Biology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
- These authors contributed equally to this work
| | - Jung Shan Hwang
- Center for Information Biology-DNA Data Bank of Japan, National Institute of Genetics, Mishima 411-8540, Japan
- These authors contributed equally to this work
| | - Alexander Wolf
- Helmholtz Zentrum München - German Research Center of Environmental Health, Institute of Molecular Toxicology and Pharmacology, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
- These authors contributed equally to this work
| | - Angelika Böttger
- Department Biologie II, Ludwig Maximilians University, Munich 80539, Germany
| | - Hiroshi Shimizu
- Department of Developmental Genetics, National Institute of Genetics, Mishima 411-8540, Japan
| | - Charles N. David
- Department Biologie II, Ludwig Maximilians University, Munich 80539, Germany
| | - Takashi Gojobori
- Biological and Environmental Science and Engineering Division and Computational Bioscience Research Center, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia
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Abedin M, King N. Diverse evolutionary paths to cell adhesion. Trends Cell Biol 2010; 20:734-42. [PMID: 20817460 DOI: 10.1016/j.tcb.2010.08.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 07/24/2010] [Accepted: 08/03/2010] [Indexed: 12/24/2022]
Abstract
The morphological diversity of animals, fungi, plants, and other multicellular organisms stems from the fact that each lineage acquired multicellularity independently. A prerequisite for each origin of multicellularity was the evolution of mechanisms for stable cell-cell adhesion or attachment. Recent advances in comparative genomics and phylogenetics provide critical insights into the evolutionary foundations of cell adhesion. Reconstructing the evolution of cell junction proteins in animals and their unicellular relatives exemplifies the roles of co-option and innovation. Comparative studies of volvocine algae reveal specific molecular changes that accompanied the evolution of multicellularity in Volvox. Comparisons between animals and Dictyostelium show how commonalities and differences in the biology of unicellular ancestors influenced the evolution of adhesive mechanisms. Understanding the unicellular ancestry of cell adhesion helps illuminate the basic cell biology of multicellular development in modern organisms.
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Affiliation(s)
- Monika Abedin
- Department of Molecular and Cell Biology, Division of Genetics, Genomics, and Development, University of California at Berkeley, Berkeley, California 94720-3200, USA
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Steele RE, David CN, Technau U. A genomic view of 500 million years of cnidarian evolution. Trends Genet 2010; 27:7-13. [PMID: 21047698 DOI: 10.1016/j.tig.2010.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 09/23/2010] [Accepted: 10/08/2010] [Indexed: 01/29/2023]
Abstract
Cnidarians (corals, anemones, jellyfish and hydras) are a diverse group of animals of interest to evolutionary biologists, ecologists and developmental biologists. With the publication of the genome sequences of Hydra and Nematostella, whose last common ancestor was the stem cnidarian, researchers are beginning to see the genomic underpinnings of cnidarian biology. Cnidarians are known for the remarkable plasticity of their morphology and life cycles. This plasticity is reflected in the Hydra and Nematostella genomes, which differ to an exceptional degree in size, base composition, transposable element content and gene conservation. It is now known what cnidarian genomes, given 500 million years, are capable of; as we discuss here, the next challenge is to understand how this genomic history has led to the striking diversity seen in this group.
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Affiliation(s)
- Robert E Steele
- Department of Biological Chemistry and the Developmental Biology Center, University of California, Irvine, CA 92697, USA.
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Scappaticci A, Kahn F, Kass-Simon G. Nematocyst discharge in Hydra vulgaris: Differential responses of desmonemes and stenoteles to mechanical and chemical stimulation. Comp Biochem Physiol A Mol Integr Physiol 2010; 157:184-91. [DOI: 10.1016/j.cbpa.2010.06.177] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/15/2010] [Accepted: 06/16/2010] [Indexed: 11/15/2022]
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Magie CR, Martindale MQ. Cell-cell adhesion in the cnidaria: insights into the evolution of tissue morphogenesis. THE BIOLOGICAL BULLETIN 2008; 214:218-232. [PMID: 18574100 DOI: 10.2307/25470665] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Cell adhesion is a major aspect of cell biology and one of the fundamental processes involved in the development of a multicellular animal. Adhesive mechanisms, both cell-cell and between cell and extracellular matrix, are intimately involved in assembling cells into the three-dimensional structures of tissues and organs. The modulation of adhesive complexes could therefore be seen as a central component in the molecular control of morphogenesis, translating information encoded within the genome into organismal form. The availability of whole genomes from early-branching metazoa such as cnidarians is providing important insights into the evolution of adhesive processes by allowing for the easy identification of the genes involved in adhesion in these organisms. Discovery of the molecular nature of cell adhesion in the early-branching groups, coupled with comparisons across the metazoa, is revealing the ways evolution has tinkered with this vital cellular process in the generation of the myriad forms seen across the animal kingdom.
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Affiliation(s)
- Craig R Magie
- Kewalo Marine Laboratory, Pacific Biomedical Research Center, University of Hawai'i Honolulu, Hawaii 96813, USA
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18
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The neural net of Hydra and the modulation of its periodic activity. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/bfb0098167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Nieuwenhuys R. Comparative aspects of volume transmission, with sidelight on other forms of intercellular communication. PROGRESS IN BRAIN RESEARCH 2001; 125:49-126. [PMID: 11098653 DOI: 10.1016/s0079-6123(00)25006-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Grimmelikhuijzen CJ, Leviev I, Carstensen K. Peptides in the nervous systems of cnidarians: structure, function, and biosynthesis. INTERNATIONAL REVIEW OF CYTOLOGY 1996; 167:37-89. [PMID: 8768492 DOI: 10.1016/s0074-7696(08)61345-5] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cnidarians are the lowest animal group having a nervous system and it was probably within this phylum or in a related ancestor group that nervous systems first evolved. The primitive nervous systems of cnidarians are strongly peptidergic. From a single sea anemone species, Anthopleura elegantissima, 17 different neuropeptides have been isolated so far, and we expect that many more neuropeptides (more than 30) must be present. All peptides are localized in neurons of cnidarians and we have demonstrated the presence of some of the peptides in neurosecretory dense-cored vesicles. Most neuropeptides have an excitatory or inhibitory action on whole cnidarians, muscle preparations, and isolated muscle cells, suggesting that these peptides are neurotransmitters or neuromodulators. One neuropeptide induces metamorphosis in planula larvae to become a polyp. This shows that cnidarian neuropeptides also are involved in developmental processes, such as cell differentiation and pattern formation. We have cloned the preprohormones for most of the cnidarian neuropeptides. These preprohormones have a high copy number of the immature neuropeptide sequence, which can be up to 37 neuropeptide copies per precursor molecule. In addition to well-known, "classical" processing enzymes, novel prohormone processing enzymes must be present in cnidarian neurons. These include a processing enzyme hydrolyzing at the C-terminal sides of acidic (Asp and Glu) residues and a dipeptidyl aminopeptidase digesting at the C-terminal sides of N-terminally located X-Pro and X-Ala sequences. All this shows that the primitive nervous systems of cnidarians are already quite complex, and that neuropeptides play a central role in the physiology of these animals.
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Abstract
Cnidarians have simple nervous systems and it was probably within this group or a closely-related ancestor that nervous systems first evolved. The basic plan of the cnidarian nervous system is that of a nerve net which, at some locations, has condensed to form nerve plexuses, or circular or longitudinal nerve tracts which may be syncytia. At the ultrastructural level, many cnidarian neurons have the combined characteristics of sensory, motor, inter- and neurosecretory neurons and thus appear to be multifunctional. We propose that these multifunctional neurons resemble the ancestors of the more specialized neurons that we find in higher animals today. The primitive nervous system of cnidarians is strongly peptidergic: from a single sea anemone species Anthopleura elegantissima, we have now isolated 16 different novel neuropeptides. These peptides are biologically active and cause inhibitions or contractions in muscle preparations or isolated muscle cells from sea anemones. The various peptides are located in at least six distinct sets of neurons showing that sea anemone neurons have already specialized with respect to their peptide content. Using immuno-electronmicroscopy, we have found that the peptides are located in neuronal dense-cored vesicles associated with both synaptic and non-synaptic release sites. All these data indicate that evolutionarily "old" nervous systems use peptides as transmitters. We have also investigated the biosynthesis of the cnidarian neuropeptides. These neuropeptides are made as large precursor proteins which contain multiple (up to 36) copies of immature neuropeptides. Thus, the biosynthesis of neuropeptides in cnidarians is very efficient and comparable to that of higher invertebrates, such as molluscs and insects, and vertebrates.
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23
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Hufnagel LA, Kass-Simon G, Lyon MK. Functional organization of battery cell complexes in tentacles ofHydra attenuata. J Morphol 1985; 184:323-341. [DOI: 10.1002/jmor.1051840307] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kinnamon JC, Taylor BJ, Delay RJ, Roper SD. Ultrastructure of mouse vallate taste buds. I. Taste cells and their associated synapses. J Comp Neurol 1985; 235:48-60. [PMID: 3989005 DOI: 10.1002/cne.902350105] [Citation(s) in RCA: 136] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ultrastructural features of murine vallate taste bud cells and their associated synapses have been examined in thin and thick sections with conventional transmission electron microscopy and high-voltage electron microscopy. Computer-assisted reconstructions from serial sections were utilized to aid in visualization of taste bud cell-nerve fiber synapses. We have classified taste bud cells on the basis of previously established criteria-namely, size of the nucleus, shape and density of chromatin, density of cytoplasm, and presence or absence of dense-cored or clear vesicles, other cytoplasmic organelles, and synaptic foci. Both dark cells and light cells are present, as well as cells with intermediate morphological characteristics. Synapses were observed from taste bud cells onto nerve fiber processes. In virtually all instances, synapses are associated with the nuclear region of the taste cell. These synapses are characterized by the presence of 40-70 nm clear vesicles embedded in a thickened presynaptic membrane separated from the postsynaptic membrane by a 16-30 nm cleft. Synapses are not unique to any particular cell type. Dark, intermediate, and light cells all synapse onto nerve fibers. Two general types of synapses exist: spot (or macular) and fingerlike. In the latter, the postsynaptic region of the neuronal process protrudes into an invagination of the taste cell membrane. Differences in synaptic morphology are not correlated with taste cell type. In some cases a single taste cell was observed to possess both macular and fingerlike synapses adjacent to one another, forming a synaptic complex onto a single neuronal process. On the basis of the presence of synaptic contacts, we conclude that both "dark" and "light" cells are gustatory receptors.
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Westfall JA, Argast DR, Kinnamon JC. Numbers, distribution, and types of neurons in the pedal disk of Hydra based on a serial reconstruction from transmission electron micrographs. J Morphol 1983; 178:95-103. [PMID: 6655698 DOI: 10.1002/jmor.1051780202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The numbers, distribution, and types of neurons in a pedal disk of Hydra littoralis were determined from electron micrographs of 567 serial sections approximately 0.12 micron thick. Of 248 neurons counted, we found 234 ganglion cells in the epidermis and 14 in the gastrodermis. No sensory cells with surface projecting cilia were observed in either epithelial layer of the foot region. We found ciliary structures in 196 (84%) of the epidermal neurons: 55 had a well defined cilium-stereociliary complex, 30 had a cilium lacking stereocilia, and 111 could not be classified. In contrast, 38 epidermal neurons lacked evidence of ciliary structures; 10 of the 14 gastrodermal neurons had one or more centrioles, some with an elaborate pericentriolar rootlet system, but no cilium or stereocilia. Neuronal perikarya could be classified into those with dense heterochromatic nuclei and those with light granular nuclei; often these two nuclear variations were observed in paired or triad arrangements of epidermal neurons. In addition, 68 (29%) of the epidermal neurons were characterized by the presence of small dense granules (115-178 nm in diameter) in the cytoplasm around the periciliary space. Although 32 pairs and 5 triads of contiguous neuronal perikarya were present in the epidermis, only two paired neuronal perikarya were present in the gastrodermis. The major concentration of neurons was approximately midway between the basal surface and the region of transition of epitheliomuscular cells into glandulomuscular cells. There was no evidence of large neuronal aggregations suggestive of ganglia in the pedal disk.
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Larsen WJ. Biological implications of gap junction structure, distribution and composition: a review. Tissue Cell 1983; 15:645-71. [PMID: 6359583 DOI: 10.1016/0040-8166(83)90041-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Traditionally, all gap junctions have been considered to be identical in structure and function throughout the animal kingdom. Functions ascribed to these membrane specializations have been fundamental and have not been thought to differ significantly with respect to their mechanism of action. More recent studies support the view, however, that structural and compositional diversity may reflect significant functional differences between gap junctions in different classes of tissue but no clear and definitive patterns have yet emerged. This review does not attempt to comprehensively analyze the totality of the vast gap junction and coupling literature but focuses instead upon those recent observations which raise new questions related to the biological activities of gap junctions in different tissues.
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Kinnamon JC, Westfall JA. Types of neurons and synaptic connections at hypostome-tentacle junctions in Hydra. J Morphol 1982; 173:119-28. [PMID: 7108966 DOI: 10.1002/jmor.1051730110] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using transmission electron microscopy of thin sections we have examined neuronal concentrations at hypostome-tentacle junctions in Hydra littoralis. A total of 194 ganglion cells were counted in 587 serial thin sections of a single hypostome-tentacle junction. We found two distinct types of ganglion cells: those with and those lacking stereocilia. The majority of the neurons observed lacked stereocilia; in a single hypostome-tentacle junction only 37% of the ganglion cells possessed a kinocilium surrounded by rodlike stereocilia. Most of the ganglion cells (55%) were clustered together in the oral or upper epidermis of the hypostome-tentacle junction: Nineteen percent were in the lateral and 26% in the aboral or lower epidermis. The two types of ganglion cells did not differ significantly in their distribution. Both types of ganglion cell had synaptic contacts with other neurons and with epitheliomuscular cells. More than 85% of the neuroneuronal and 61% of the neuroepitheliomuscular cell synapses were located in the oral epidermis of a hypostome-tentacle junction. In addition, two-way chemical synapses and a gap junction between neurons were observed at hypostome-tentacle junctions. Our morphological evidence of synaptic connectivity in neuronal clusters at hypostome-tentacle junctions suggests that primitive ganglia are present in Hydra.
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