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Tanaka A, Umatani C, Oka Y. Acetylcholine Inhibits Spontaneous Firing Activity of Terminal Nerve GnRH Neurons in Medaka. Zoolog Sci 2023; 40:151-159. [PMID: 37042694 DOI: 10.2108/zs220070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/04/2023] [Indexed: 03/17/2023]
Abstract
Vertebrates generally possess hypophysiotropic and non-hypophysiotropic gonadotropin releasing hormone (GnRH) neurons. The terminal nerve (TN) GnRH neurons are known to belong to the non-hypophysiotropic neurons and have been suggested to modulate sexual behaviors. These neurons show spontaneous pacemaker firing activity and release neuropeptides GnRH and neuropeptide FF. Since the spontaneous firing activities of peptidergic neurons, including GnRH neurons, are believed to play important roles in the release of neuropeptides, understanding the regulatory mechanisms of these spontaneous firing activities is important. Here, we analyzed firing activities of the TN-GnRH neurons in medaka during application of acetylcholine (ACh), which is one of the essential neuromodulators in the brain. Whole cell patch clamp recording of TN-GnRH neurons demonstrated that ACh induces hyperpolarization and inhibits their pacemaker firing. Electrophysiological analysis using an antagonist for acetylcholine receptors and in situ hybridization analysis showed that firing of TN-GnRH neurons is inhibited via M2-type muscarinic acetylcholine receptor. These findings, taken together with literature from several other fish species (including teleosts and elasmobranchs), indicate that ACh may generally play an inhibitory role in modulating spontaneous activities of TN-GnRH neurons and thereby sexual behaviors in fish.
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Affiliation(s)
- Aiki Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Chie Umatani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Afferent and efferent connections of the nucleus posterior tuberis in the firemouth cichlid, Thorichthys meeki. Neurosci Res 2023; 186:10-20. [PMID: 36007624 DOI: 10.1016/j.neures.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 01/04/2023]
Abstract
The nucleus posterior tuberis (NPT) in teleost fishes, also called posterior tuberal nucleus, is situated in the posterior tuberculum of the diencephalon. It is fused across the midline and densely packed with small cells, but little is known about its connections. In this study, the afferent and efferent connections of the NPT were examined by means of tracer applications of the carbocyanine dye DiI in the firemouth cichlid, Thorichthys meeki. Retrogradely labeled cell bodies were found in the corpus mamillare and nucleus periventricularis of the inferior lobe; and anterogradely labeled terminal fibers were detected in the medial zone of the dorsal telencephalon, medial part of the nucleus lateralis tuberis, dorsal posterior thalamic nucleus, torus lateralis, medial part of the nucleus diffusus of the inferior lobe, and tectum opticum. All these connections show an ipsilateral tendency. The NPT is apparently a significant relay nucleus in the diencephalon of T. meeki, and possibly involved in a variety of feedback circuits. It seems also to be part of a tecto-hypothalamo-telencephalic pathway in cichlids.
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3
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Umatani C, Yoshida N, Yamamoto E, Akazome Y, Mori Y, Kanda S, Okubo K, Oka Y. Co-existing Neuropeptide FF and Gonadotropin-Releasing Hormone 3 Coordinately Modulate Male Sexual Behavior. Endocrinology 2022; 163:6486464. [PMID: 34962983 DOI: 10.1210/endocr/bqab261] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 11/19/2022]
Abstract
Animals properly perform sexual behaviors by using multiple sensory cues. However, neural mechanisms integrating multiple sensory cues and regulating motivation for sexual behaviors remain unclear. Here, we focused on peptidergic neurons, terminal nerve gonadotropin-releasing hormone (TN-GnRH) neurons, which receive inputs from various sensory systems and co-express neuropeptide FF (NPFF) in addition to GnRH. Our behavioral analyses using knockout medaka of GnRH (gnrh3) and/or NPFF (npff) demonstrated that some sexual behavioral repertoires were delayed, not disrupted, in gnrh3 and npff single knockout males, while the double knockout appeared to alleviate the significant defects that were observed in single knockouts. We also found anatomical evidence to show that both neuropeptides modulate the sexual behavior-controlling brain areas. Furthermore, we demonstrated that NPFF activates neurons in the preoptic area via indirect pathway, which is considered to induce the increase in motivation for male sexual behaviors. Considering these results, we propose a novel mechanism by which co-existing peptides of the TN-GnRH neurons, NPFF, and GnRH3 coordinately modulate certain neuronal circuit for the control of behavioral motivation. Our results may go a long way toward understanding the functional significance of peptidergic neuromodulation in response to sensory information from the external environments.
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Affiliation(s)
- Chie Umatani
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Nagisa Yoshida
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Eri Yamamoto
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Yasuhisa Akazome
- Department of Anatomy, St. Marianna University School of Medicine, Kanagawa, Japan
| | - Yasutaka Mori
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
| | - Shinji Kanda
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, the University of Tokyo, Chiba, Japan
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Tokyo, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, Japan
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4
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Yamamoto N, Yoshimoto M. Obituary: Hironobu Ito, M.D., Ph.D. (1939–2020). J Comp Neurol 2021. [DOI: 10.1002/cne.25016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences Nagoya University Nagoya Japan
| | - Masami Yoshimoto
- Department of Rehabilitation Sciences University of Tokyo Health Sciences Tokyo Japan
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Ogawa S, Pfaff DW, Parhar IS. Fish as a model in social neuroscience: conservation and diversity in the social brain network. Biol Rev Camb Philos Soc 2021; 96:999-1020. [PMID: 33559323 DOI: 10.1111/brv.12689] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/21/2022]
Abstract
Mechanisms for fish social behaviours involve a social brain network (SBN) which is evolutionarily conserved among vertebrates. However, considerable diversity is observed in the actual behaviour patterns amongst nearly 30000 fish species. The huge variation found in socio-sexual behaviours and strategies is likely generated by a morphologically and genetically well-conserved small forebrain system. Hence, teleost fish provide a useful model to study the fundamental mechanisms underlying social brain functions. Herein we review the foundations underlying fish social behaviours including sensory, hormonal, molecular and neuroanatomical features. Gonadotropin-releasing hormone neurons clearly play important roles, but the participation of vasotocin and isotocin is also highlighted. Genetic investigations of developing fish brain have revealed the molecular complexity of neural development of the SBN. In addition to straightforward social behaviours such as sex and aggression, new experiments have revealed higher order and unique phenomena such as social eavesdropping and social buffering in fish. Finally, observations interpreted as 'collective cognition' in fish can likely be explained by careful observation of sensory determinants and analyses using the dynamics of quantitative scaling. Understanding of the functions of the SBN in fish provide clues for understanding the origin and evolution of higher social functions in vertebrates.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, 47500, Malaysia
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, Rockefeller University, New York, NY, 10065, U.S.A
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, 47500, Malaysia
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Schmidt M. Calretinin immunoreactivity in the inferior lobe of the hypothalamus and associated nuclei of the firemouth cichlid, Thorichthys meeki. J Chem Neuroanat 2020; 113:101887. [PMID: 33189868 DOI: 10.1016/j.jchemneu.2020.101887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/12/2020] [Accepted: 11/10/2020] [Indexed: 11/19/2022]
Abstract
The distribution of the calcium-binding protein calretinin (CR) was examined by an immunohistochemical method using specific antibodies. CR is involved in the visual system, and the inferior lobe of the hypothalamus represents a multisensory integration center in cichlids. The focus of the present study was to analyze the distribution of CR immunoreactivity in a cichlid fish, the firemouth cichlid, Thorichthys meeki, for the hypothalamic inferior lobe and for the torus lateralis, nucleus glomerulosus, nucleus posterior tuberis, and corpus mamillare as associated nuclei of the hypothalamus. CR-immunoreactive (CR-ir) cell bodies were visualized in the lateral and medial part of the diffuse nucleus of the inferior lobe, ventral portion of the central nucleus of the inferior lobe, torus lateralis, nucleus glomerulosus, and nucleus posterior tuberis. CR-ir fibers could be detected in the dorsal portion of the central nucleus of the inferior lobe and corpus mamillare. The strongest labeling of CR-ir neuropil was observed in the lateral part of the diffuse nucleus of the inferior lobe, outer zone of the periventricular nucleus of the inferior lobe, torus lateralis, nucleus glomerulosus, and nucleus posterior tuberis. CR is abundantly present in the inferior lobe of the hypothalamus and associated nuclei. The role of CR in highly active processes in the inferior lobe of cichlids will be discussed.
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Affiliation(s)
- Matthias Schmidt
- Institute of Zoology, University of Bonn, Meckenheimer Allee 169, 53115 Bonn, Germany.
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Muñoz-Cueto JA, Zmora N, Paullada-Salmerón JA, Marvel M, Mañanos E, Zohar Y. The gonadotropin-releasing hormones: Lessons from fish. Gen Comp Endocrinol 2020; 291:113422. [PMID: 32032603 DOI: 10.1016/j.ygcen.2020.113422] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 12/26/2022]
Abstract
Fish have been of paramount importance to our understanding of vertebrate comparative neuroendocrinology and the mechanisms underlying the physiology and evolution of gonadotropin-releasing hormones (GnRH) and their genes. This review integrates past and recent knowledge on the Gnrh system in the fish model. Multiple Gnrh isoforms (two or three forms) are present in all teleosts, as well as multiple Gnrh receptors (up to five types), which differ in neuroanatomical localization, pattern of projections, ontogeny and functions. The role of the different Gnrh forms in reproduction seems to also differ in teleost models possessing two versus three Gnrh forms, Gnrh3 being the main hypophysiotropic hormone in the former and Gnrh1 in the latter. Functions of the non-hypothalamic Gnrh isoforms are still unclear, although under suboptimal physiological conditions (e.g. fasting), Gnrh2 may increase in the pituitary to ensure the integrity of reproduction under these conditions. Recent developments in transgenesis and mutagenesis in fish models have permitted the generation of fish lines expressing fluorophores in Gnrh neurons and to elucidate the dynamics of the elaborate innervations of the different neuronal populations, thus enabling a more accurate delineation of their reproductive roles and regulations. Moreover, in combination with neuronal electrophysiology, these lines have clarified the Gnrh mode of actions in modulating Lh and Fsh activities. While loss of function and genome editing studies had the premise to elucidate the exact roles of the multiple Gnrhs in reproduction and other processes, they have instead evoked an ongoing debate about these roles and opened new avenues of research that will no doubt lead to new discoveries regarding the not-yet-fully-understood Gnrh system.
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Affiliation(s)
- José A Muñoz-Cueto
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, The European University of the Seas (SEA-EU), Puerto Real (Cádiz), Spain.
| | - Nilli Zmora
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - José A Paullada-Salmerón
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, The European University of the Seas (SEA-EU), Puerto Real (Cádiz), Spain
| | - Miranda Marvel
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Evaristo Mañanos
- Institute of Aquaculture of Torre de la Sal, CSIC, Castellón, Spain
| | - Yonathan Zohar
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD, USA.
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8
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Umatani C, Oka Y. Multiple functions of non-hypophysiotropic gonadotropin releasing hormone neurons in vertebrates. ZOOLOGICAL LETTERS 2019; 5:23. [PMID: 31367467 PMCID: PMC6647275 DOI: 10.1186/s40851-019-0138-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 06/19/2019] [Indexed: 06/10/2023]
Abstract
Gonadotropin releasing hormone (GnRH) is a hypophysiotropic hormone that is generally thought to be important for reproduction. This hormone is produced by hypothalamic GnRH neurons and stimulates the secretion of gonadotropins. On the other hand, vertebrates also have non-hypophysiotropic GnRH peptides, which are produced by extrahypothalamic GnRH neurons. They are mainly located in the terminal nerve, midbrain tegmentum, trigeminal nerve, and spinal cord (sympathetic preganglionic nerves). In vertebrates, there are typically three gnrh paralogues (gnrh1, gnrh2, gnrh3). GnRH-expression in the non-hypophysiotropic neurons (gnrh1 or gnrh3 in the terminal nerve and the trigeminal nerve, gnrh2 in the midbrain tegmentum) occurs from the early developmental stages. Recent studies have suggested that non-hypophysiotropic GnRH neurons play various functional roles. Here, we summarize their anatomical/physiological properties and discuss their possible functions, focusing on studies in vertebrates. GnRH neurons in the terminal nerve show different spontaneous firing properties during the developmental stages. These neurons in adulthood show regular pacemaker firing, and it has been suggested that these neurons show neuromodulatory function related to the regulation of behavioral motivation, etc. In addition to their recognized role in neuromodulation in adult, in juvenile fish, these neurons, which show more frequent burst firing than in adults, are suggested to have novel functions. GnRH neurons in the midbrain tegmentum show regular pacemaker firing similar to that of the adult terminal nerve and are suggested to be involved in modulations of feeding (teleosts) or nutrition-related sexual behaviors (musk shrew). GnRH neurons in the trigeminal nerve are suggested to be involved in nociception and chemosensory avoidance, although the literature on their electrophysiological properties is limited. Sympathetic preganglionic cells in the spinal cord were first reported as peptidergic modulatory neurons releasing GnRH with a putative function in coordinating interaction between vasomotor and exocrine outflow in the sympathetic nervous system. The functional role of non-hypophysiotropic GnRH neurons may thus be in the global modulation of neural circuits in a manner dependent on internal conditions or the external environment.
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Affiliation(s)
- Chie Umatani
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, 113-0033 Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Tokyo, 113-0033 Japan
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Nakayama T, Nishino H, Narita J, Abe H, Yamamoto N. Indirect pathway to pectoral fin motor neurons from nucleus ruber in the Nile tilapia Oreochromis niloticus. J Comp Neurol 2019; 527:957-971. [PMID: 30408166 DOI: 10.1002/cne.24578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 11/10/2022]
Abstract
Supraspinal motor control systems of pectoral fins remain unclear in teleosts. Nucleus ruber of Goldstein (1905; NRg), which has been identified as the probable homologue of nucleus ruber of tetrapods, is a candidate structure serving for such functions. In the present study, we investigated possible involvement of the NRg in the control of pectoral fin movement by tract-tracing experiments in the Nile tilapia Oreochromis niloticus. Tracer injections into the NRg revealed the fiber course of rubrospinal tract. Rubrospinal fibers crossed the midline at the level of midbrain, descended through the tegmentum, and terminated in a region ventrally adjacent to the dorsal horn at the spinomedullary junction, without reaching the ventral horn where pectoral fin motor neurons are present. Tracer injection experiments into the dorsal horn region resulted in labeled terminals in proximities of presumed pectoral fin motor neurons in the ventral horn. Tracer injection experiments into the ventral horn resulted in retrogradely labeled neurons ventrally adjacent to the dorsal horn, where labeled terminals were detected following rubral injections. These anatomical analyses suggest that the NRg of actinopterygians is involved in the control of pectoral fin motor neurons through an indirect pathway via interneurons in the dorsal horn.
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Affiliation(s)
- Tomoya Nakayama
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hirotaka Nishino
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Junya Narita
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hideki Abe
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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Bloch S, Thomas M, Colin I, Galant S, Machado E, Affaticati P, Jenett A, Yamamoto K. Mesencephalic origin of the inferior lobe in zebrafish. BMC Biol 2019; 17:22. [PMID: 30849972 PMCID: PMC6407210 DOI: 10.1186/s12915-019-0631-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/22/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although the overall brain organization is shared in vertebrates, there are significant differences within subregions among different groups, notably between Sarcopterygii (lobe-finned fish) and Actinopterygii (ray-finned fish). Recent comparative studies focusing on the ventricular morphology have revealed a large diversity of the hypothalamus. Here, we study the development of the inferior lobe (IL), a prominent structure forming a bump on the ventral surface of the teleost brain. Based on its position, IL has been thought to be part of the hypothalamus (therefore forebrain). RESULTS Taking advantage of genetic lineage-tracing techniques in zebrafish, we reveal that cells originating from her5-expressing progenitors in the midbrain-hindbrain boundary (MHB) participate in the formation of a large part of the IL. 3D visualization demonstrated how IL develops in relation to the ventricular system. We found that IL is constituted by two developmental components: the periventricular zone of hypothalamic origin and the external zone of mesencephalic origin. The mesencephalic external zone grows progressively until adulthood by adding new cells throughout development. CONCLUSION Our results disprove a homology between the IL and the mammalian lateral hypothalamus. We suggest that the IL is likely to be involved in multimodal sensory integration rather than feeding motivation. The teleost brain is not a simpler version of the mammalian brain, and our study highlights the evolutionary plasticity of the brain which gives rise to novel structures.
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Affiliation(s)
- Solal Bloch
- Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS UMR9197, Univ Paris Sud, Université Paris-Saclay, CNRS Bâtiment 5, Avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Manon Thomas
- Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS UMR9197, Univ Paris Sud, Université Paris-Saclay, CNRS Bâtiment 5, Avenue de la Terrasse, 91190, Gif-sur-Yvette, France
- Present address: Plateau de phénotypage TEFOR, LPGP-INRA UR1037, 35042, Rennes, France
| | - Ingrid Colin
- Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS UMR9197, Univ Paris Sud, Université Paris-Saclay, CNRS Bâtiment 5, Avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Sonya Galant
- Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS UMR9197, Univ Paris Sud, Université Paris-Saclay, CNRS Bâtiment 5, Avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Elodie Machado
- TEFOR Paris-Saclay, CNRS UMS2010, INRA UMS1451, Univ Paris Sud, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Pierre Affaticati
- TEFOR Paris-Saclay, CNRS UMS2010, INRA UMS1451, Univ Paris Sud, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Arnim Jenett
- TEFOR Paris-Saclay, CNRS UMS2010, INRA UMS1451, Univ Paris Sud, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Kei Yamamoto
- Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS UMR9197, Univ Paris Sud, Université Paris-Saclay, CNRS Bâtiment 5, Avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
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11
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Blin M, Tine E, Meister L, Elipot Y, Bibliowicz J, Espinasa L, Rétaux S. Developmental evolution and developmental plasticity of the olfactory epithelium and olfactory skills in Mexican cavefish. Dev Biol 2018; 441:242-251. [PMID: 29709597 DOI: 10.1016/j.ydbio.2018.04.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 11/16/2022]
Abstract
The fish Astyanax mexicanus comes in two forms: the normal surface-dwelling (SF) and the blind depigmented cave-adapted (CF) morphs. Among many phenotypic differences, cavefish show enhanced olfactory sensitivity to detect amino-acid odors and they possess large olfactory sensory organs. Here, we questioned the relationship between the size of the olfactory organ and olfactory capacities. Comparing olfactory detection abilities of CF, SF and F1 hybrids with various olfactory epithelium (OE) sizes in behavioral tests, we concluded that OE size is not the only factor involved. Other possibilities were envisaged. First, olfactory behavior was tested in SF raised in the dark or after embryonic lens ablation, which leads to eye degeneration and mimics the CF condition. Both absence of visual function and absence of visual organs improved the SF olfactory detection capacities, without affecting the size of their OE. This suggested that developmental plasticity occurs between the visual and the olfactory modalities, and can be recruited in SF after visual deprivation. Second, the development of the olfactory epithelium was compared in SF and CF in their first month of life. Proliferation, cell death, neuronal lifespan, and olfactory progenitor cell cycling properties were identical in the two morphs. By contrast, the proportions of the three main olfactory sensory neurons subtypes (ciliated, microvillous and crypt) in their OE differed. OMP-positive ciliated neurons were more represented in SF, TRPC2-positive microvillous neurons were proportionately more abundant in CF, and S100-positive crypt cells were found in equal densities in the two morphs. Thus, general proliferative properties of olfactory progenitors are identical but neurogenic properties differ and lead to variations in the neuronal composition of the OE in SF and CF. Together, these experiments suggest that there are at least two components in the evolution of cavefish olfactory skills: (1) one part of eye-dependent developmental phenotypic plasticity, which does not depend on the size of the olfactory organ, and (2) one part of developmental evolution of the OE, which may stem from embryonic specification of olfactory neurons progenitor pools.
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Affiliation(s)
- Maryline Blin
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Eugène Tine
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Lydvina Meister
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Yannick Elipot
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Jonathan Bibliowicz
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Luis Espinasa
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France.
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12
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Umatani C, Oka Y. Juvenile-Specific Burst Firing of Terminal Nerve GnRH3 Neurons Suggests Novel Functions in Addition to Neuromodulation. Endocrinology 2018; 159:1678-1689. [PMID: 29409015 DOI: 10.1210/en.2017-03210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/27/2018] [Indexed: 11/19/2022]
Abstract
Peptidergic neurons are suggested to play a key role in neuromodulation of animal behaviors in response to sensory cues in the environment. Terminal nerve gonadotropin-releasing hormone 3 (TN-GnRH3) neurons are thought to be one of the peptidergic neurons important for such neuromodulation in adult vertebrates. On the other hand, it has been reported that TN-GnRH3 neurons are labeled by a specific GnRH3 antibody from early developmental stages to adulthood and are thus suggested to produce mature GnRH3 peptide even in the early developmental stages. However, it remains unknown when TN-GnRH3 neurons show spontaneous burst firing, which is suggested to be involved in neuropeptide release. Using a whole-brain in vitro preparation of gnrh3:enhanced green fluorescent protein (EGFP) medaka fish, we first recorded spontaneous firings of TN-GnRH3 neurons after hatching to adulthood. Contrary to what one would expect from their neuromodulatory functions-that TN-GnRH3 neurons are more active in adulthood-TN-GnRH3 neurons in juveniles showed spontaneous burst firing more frequently than in adulthood (juvenile-specific burst firing). Ca2+ imaging of TN-GnRH3 neurons in juveniles may further suggest that juvenile-specific burst firing triggers neuropeptide release. Furthermore, juvenile-specific burst firing was suggested to be induced by blocking persistent GABAergic inhibition to the glutamatergic neurons, which leads to an increase in glutamatergic synaptic inputs to TN-GnRH3 neurons. The present study reports that peptidergic neurons show juvenile-specific burst firing involved in triggering peptide release and suggests that juvenile TN-GnRH3 neurons have novel functions, in addition to neuromodulation.
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Affiliation(s)
- Chie Umatani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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13
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Affiliation(s)
- Natália Madeira
- ISPA—Instituto Universitário, Lisboa, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Rui F. Oliveira
- ISPA—Instituto Universitário, Lisboa, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Champalimaud Neuroscience Program, Lisboa, Portugal
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14
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Involvement of hormones in olfactory imprinting and homing in chum salmon. Sci Rep 2016; 6:21102. [PMID: 26879952 PMCID: PMC4754751 DOI: 10.1038/srep21102] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 01/18/2016] [Indexed: 11/26/2022] Open
Abstract
The olfactory hypothesis for salmon imprinting and homing to their natal stream is well known, but the endocrine hormonal control mechanisms of olfactory memory formation in juveniles and retrieval in adults remain unclear. In brains of hatchery-reared underyearling juvenile chum salmon (Oncorhynchus keta), thyrotropin-releasing hormone gene expression increased immediately after release from a hatchery into the natal stream, and the expression of the essential NR1 subunit of the N-methyl-D-aspartate receptor increased during downstream migration. Gene expression of salmon gonadotropin-releasing hormone (sGnRH) and NR1 increased in the adult chum salmon brain during homing from the Bering Sea to the natal hatchery. Thyroid hormone treatment in juveniles enhanced NR1 gene activation, and GnRHa treatment in adults improved stream odour discrimination. Olfactory memory formation during juvenile downstream migration and retrieval during adult homing migration of chum salmon might be controlled by endocrine hormones and could be clarified using NR1 as a molecular marker.
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15
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The Conservative Evolution of the Vertebrate Basal Ganglia. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/b978-0-12-802206-1.00004-0] [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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16
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Pfister D, Yu C, Kim DS, Li J, Drewing A, Li L. Zebrafish Olfacto-Retinal Centrifugal Axon Projection and Distribution: Effects of Gonadotropin-Releasing Hormone and Dopaminergic Signaling. Dev Neurosci 2015; 38:27-33. [PMID: 26505192 DOI: 10.1159/000439524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/19/2015] [Indexed: 11/19/2022] Open
Abstract
The terminalis neurons (TNs) have been described in teleost species. In zebrafish, the TNs are located in the olfactory bulb. The TNs synthesize and release gonadotropin-releasing hormone (GnRH) as one of the major neurotransmitters. The TNs project axons to many brain areas, which include the neural retina. In the retina, the TN axons synapse with dopaminergic interplexiform cells (DA-IPCs) and retinal ganglion cells (RGCs). In this research, we examine the role of GnRH and dopaminergic signaling in TN axon projection to the retina using the transgenic zebrafish Tg(GnRH-3::GFP). While the TNs developed at 34 h postfertilization (hpf), the first TN axons were not detected in the retina until 48-50 hpf, when the first DA-IPCs were differentiated. In developing embryos, inhibition of retinal GnRH signaling pathways severely interrupted the projection of TN axons to the retina. However, inhibition of retinal dopaminergic signaling produced little effect on TN axon projection. In adult retinas, inactivation of GnRH receptors disrupted the patterns of TN axon distribution, and depletion of DA-IPCs abolished the TN axons. When DA-IPCs regenerated, the TN axons reappeared. Together, the data suggest that in developing zebrafish retinas GnRH signaling is required for TN axon projection, whereas in adult retinas activation of GnRH and dopaminergic signaling transduction is required for normal distribution of the TN axons.
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Affiliation(s)
- Delaney Pfister
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Ind., USA
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17
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Uezono S, Yamada Y, Kato T, Abe H, Yamamoto N. Connections of the commissural nucleus of Cajal in the goldfish, with special reference to the topographic organization of ascending visceral sensory pathways. J Comp Neurol 2014; 523:209-25. [PMID: 25209308 DOI: 10.1002/cne.23675] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/05/2014] [Accepted: 09/05/2014] [Indexed: 11/09/2022]
Abstract
The primary general visceral nucleus of teleosts is called the commissural nucleus of Cajal (NCC). The NCC of goldfish has been divided into the medial (NCCm) and lateral (NCCl) subnuclei that receive inputs from subdiaphragmatic gastrointestinal tract and the posterior pharynx, respectively. Fiber connections of the NCC were examined by tract-tracing methods in the goldfish Carassius auratus. Tracer injections into the NCC suggested that the NCC projects directly not only to the secondary visceral sensory region in the rhombencephalic isthmus and other brain stem centers, but also to the forebrain, similar to the situations in mammals, birds, and the Nile tilapia. Although fiber connections of the NCCm and NCCl were basically similar, the NCCm was the more important source of ascending general visceral fibers to the forebrain. Topographic organization was recognized regarding projections to the isthmic secondary visceral sensory zone; input from the NCCm is represented in the secondary general visceral sensory nucleus, while input from the NCCl in the lateral edge of the secondary gustatory nucleus. Moreover, specific injections into different regions of the vagal lobe revealed that the dorsomedio-ventrolateral axis of the lobe is represented in the lateromedial axis of the secondary gustatory nucleus. These observations suggest fine topographic organization of ascending visceral sensory pathways to the isthmic secondary centers. It should also be noted that the reception of primary afferents from the posterior pharynx and projections to the secondary gustatory nucleus suggest that the NCCl may be regarded as a gustatory rather than a general visceral sensory structure.
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Affiliation(s)
- Shiori Uezono
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
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18
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Ramallo MR, Morandini L, Alonso F, Birba A, Tubert C, Fiszbein A, Pandolfi M. The endocrine regulation of cichlids social and reproductive behavior through the eyes of the chanchita, Cichlasoma dimerus (Percomorpha; Cichlidae). ACTA ACUST UNITED AC 2014; 108:194-202. [PMID: 25159924 DOI: 10.1016/j.jphysparis.2014.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/06/2014] [Accepted: 08/13/2014] [Indexed: 01/12/2023]
Abstract
Sociobiology, the study of social behavior, calls for a laboratory model with specific requirements. Among the most obvious is the execution of social interactions that need to be readily observable, quantifiable and analyzable. If, in turn, one focuses on the neuroendocrinological basis of social behavior, restrictions grow even tighter. A good laboratory model should then allow easy access to its neurological and endocrine components and processes. During the last years, we have been studying the physiological foundation of social behavior on what we believe fits all the aforementioned requirements: the so called "chanchita", Cichlasoma dimerus. This Neotropical cichlid fish exhibits biparental care of the eggs and larvae and presents a hierarchical social system, established and sustained through agonistic interactions. The aim of the current article is to review new evidence on chanchita's social and reproductive behavior.
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Affiliation(s)
- Martín Roberto Ramallo
- Laboratorio de Neuroendocrinología y Comportamiento, IBBEA-Conicet, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Leonel Morandini
- Laboratorio de Neuroendocrinología y Comportamiento, IBBEA-Conicet, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Felipe Alonso
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Agustina Birba
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Cecilia Tubert
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Ana Fiszbein
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina
| | - Matías Pandolfi
- Laboratorio de Neuroendocrinología y Comportamiento, IBBEA-Conicet, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), CABA, Argentina.
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19
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Karigo T, Oka Y. Neurobiological study of fish brains gives insights into the nature of gonadotropin-releasing hormone 1-3 neurons. Front Endocrinol (Lausanne) 2013; 4:177. [PMID: 24312079 PMCID: PMC3832842 DOI: 10.3389/fendo.2013.00177] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/31/2013] [Indexed: 01/30/2023] Open
Abstract
Accumulating evidence suggests that up to three different molecular species of GnRH peptides encoded by different paralogs of gnrh genes are expressed by anatomically distinct groups of GnRH neurons in the brain of one vertebrate species. They are called gnrh1, gnrh2, and gnrh3. Recent evidence from molecular, anatomical, and physiological experiments strongly suggests that each GnRH system functions differently. Here, we review recent advancement in the functional studies of the three different GnRH neuron systems, mainly focusing on the electrophysiological analysis of the GnRH-green fluorescent protein (GFP) transgenic animals. The introduction of GFP-transgenic animals for the electrophysiological analysis of GnRH neurons greatly advanced our knowledge on their anatomy and electrophysiology, especially of gnrh1 neurons, which has long defied detailed electrophysiological analysis of single neurons because of their small size and scattered distribution. Based on the results of recent studies, we propose that different electrophysiological properties, especially the spontaneous patterns of electrical activities and their time-dependent changes, and the axonal projections characterize the different functions of GnRH1-3 neurons; GnRH1 neurons act as hypophysiotropic neuroendocrine regulators, and GnRH2 and GnRH3 neurons act as neuromodulators in wide areas of the brain.
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Affiliation(s)
- Tomomi Karigo
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- *Correspondence: Yoshitaka Oka, Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan e-mail:
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20
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Esposti F, Johnston J, Rosa JM, Leung KM, Lagnado L. Olfactory stimulation selectively modulates the OFF pathway in the retina of zebrafish. Neuron 2013; 79:97-110. [PMID: 23849198 PMCID: PMC3710973 DOI: 10.1016/j.neuron.2013.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2013] [Indexed: 01/11/2023]
Abstract
Cross-modal regulation of visual performance by olfactory stimuli begins in the retina, where dopaminergic interneurons receive projections from the olfactory bulb. However, we do not understand how olfactory stimuli alter the processing of visual signals within the retina. We investigated this question by in vivo imaging activity in transgenic zebrafish expressing SyGCaMP2 in bipolar cell terminals and GCaMP3.5 in ganglion cells. The food-related amino acid methionine reduced the gain and increased sensitivity of responses to luminance and contrast transmitted through OFF bipolar cells but not ON. The effects of olfactory stimulus were blocked by inhibiting dopamine uptake and release. Activation of dopamine receptors increased the gain of synaptic transmission in vivo and potentiated synaptic calcium currents in isolated bipolar cells. These results indicate that olfactory stimuli alter the sensitivity of the retina through the dopaminergic regulation of presynaptic calcium channels that control the gain of synaptic transmission through OFF bipolar cells. Olfactory stimuli regulate transmission of signals through retinal bipolar cells Modulation of synaptic gain and sensitivity occur in OFF bipolar cells but not ON An inhibitor of dopamine uptake blocks odor-induced changes in synaptic gain Dopamine potentiates presynaptic calcium channels in isolated bipolar cells
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Affiliation(s)
- Federico Esposti
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
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21
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Rosillo JC, Olivera-Bravo S, Casanova G, García-Verdugo JM, Fernández AS. Olfacto-retinalis pathway in Austrolebias charrua fishes: a neuronal tracer study. Neuroscience 2013; 253:304-15. [PMID: 24012745 DOI: 10.1016/j.neuroscience.2013.08.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 08/06/2013] [Accepted: 08/24/2013] [Indexed: 11/17/2022]
Abstract
The olfacto-retinal centrifugal system, a constant component of the central nervous system that appears to exist in all vertebrate groups, is part of the terminal nerve (TN) complex. TN allows the integration of different sensory modalities, and its anatomic variability may have functional and evolutionary significance. We propose that the olfacto-retinal branch of TN is an important anatomical link that allows the functional interaction between olfactory and visual systems in Austrolebias. By injecting three different neuronal tracers (biocytin, horseradish peroxidase, and 1,1'-dioctadecyl-3,3,3',3'tetramethyl-indocarbocyanine perchlorate (DiI)) in the left eye of Austrolebias charrua fishes, we identified the olfacto-retinal branch of TN and related neuronal somas that were differentiable by location, shape, and size. The olfacto-retinal TN branch is composed of numerous thin axons that run ventrally along the olfactory bulb (OB) and telencephalic lobes, and appears to originate from a group of many small monopolar neurons located in the rostral portion of both the ipsi- and contralateral OB (referred to as region 1). Labeled cells were found in two other regions: bipolar and multipolar neurons in the transition between the OB and telencephalic lobes (region 2) and two other groups in the preoptic/pretectal area (region 3). In this last region, the most rostral group is constituted by monopolar pear-shaped neurons and may belong to the septo-preoptic TN complex. The second group, putatively located in the pretectal region, is formed by pseudounipolar neurons and coincides with a conserved vertebrate nucleus of the centrifugal retinal system not involved in the TN complex. The found that connections between the olfactory and visual systems via the olfacto-retinal TN branch suggest an early interaction between these sensory modalities, and contribute to the identification of their currently unknown circuital organization.
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Affiliation(s)
- J C Rosillo
- Neuroanatomía Comparada, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Avenida Italia 3318, Montevideo 11600, Uruguay.
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22
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Kawai T, Abe H, Oka Y. Burst generation mediated by cholinergic input in terminal nerve-gonadotrophin releasing hormone neurones of the goldfish. J Physiol 2013; 591:5509-23. [PMID: 23959678 DOI: 10.1113/jphysiol.2013.258343] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Peptidergic neurones play a pivotal role in the neuromodulation of widespread areas in the nervous system. Generally, it has been accepted that the peptide release from these neurones is regulated by their firing activities. The terminal nerve (TN)-gonadotrophin releasing hormone (GnRH) neurones, which are one of the well-studied peptidergic neurones in vertebrate brains, are characterised by their spontaneous regular pacemaker activities, and GnRH has been suggested to modulate the sensory responsiveness of animals. Although many peptidergic neurones are known to exhibit burst firing activities when they release the peptides, TN-GnRH neurones show spontaneous burst firing activities only infrequently. Thus, it remains to be elucidated whether the TN-GnRH neurones show burst activities and, if so, how the mode switching between the regular pacemaking and bursting modes is regulated in these neurones. In this study, we found that only a single pulse electrical stimulation of the neuropil surrounding the TN-GnRH neurones reproducibly induces transient burst activities in TN-GnRH neurones. Our combined physiological and morphological data suggest that this phenomenon occurs following slow inhibitory postsynaptic potentials mediated by cholinergic terminals surrounding the TN-GnRH neurones. We also found that the activation of muscarinic acetylcholine receptors induces persistent opening of potassium channels, resulting in a long-lasting hyperpolarisation. This long hyperpolarisation induces sustained rebound depolarisation that has been suggested to be generated by a combination of persistent voltage-gated Na(+) channels and low-voltage-activated Ca(2+) channels. These new findings suggest a novel type of cholinergic regulation of burst activities in peptidergic neurones, which should contribute to the release of neuropeptides.
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Affiliation(s)
- Takafumi Kawai
- Y. Oka: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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23
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Hinz C, Kobbenbring S, Kress S, Sigman L, Müller A, Gerlach G. Kin recognition in zebrafish, Danio rerio, is based on imprinting on olfactory and visual stimuli. Anim Behav 2013. [DOI: 10.1016/j.anbehav.2013.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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24
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Servili A, Herrera-Pérez P, Kah O, Muñoz-Cueto JA. The retina is a target for GnRH-3 system in the European sea bass, Dicentrarchus labrax. Gen Comp Endocrinol 2012; 175:398-406. [PMID: 22138555 DOI: 10.1016/j.ygcen.2011.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/21/2011] [Accepted: 11/11/2011] [Indexed: 12/11/2022]
Abstract
The European sea bass expresses three GnRH (Gonadotrophin Releasing Hormone) forms that exert pleiotropic actions via several classes of receptors. The GnRH-1 form is responsible for the endogenous regulation of gonadotrophin release by the pituitary gland but the role of GnRH-2 and GnRH-3 remains unclear in fish. In a previous study performed in sea bass, we have provided evidence of direct links between the GnRH-2 cells and the pineal organ and demonstrated a functional role for GnRH-2 in the modulation of the secretory activity of this photoreceptive organ. In this study, we have investigated the possible relationship between the GnRH-3 system and the retina in the same species. Thus, using a biotinylated dextran-amine tract-tracing method, we reveal the presence of retinopetal cells in the terminal nerve of sea bass, a region that also contains GnRH-3-immunopositive cells. Moreover, GnRH-3-immunoreactive fibers were observed at the boundary between the inner nuclear and the inner plexiform layers, and also within the ganglion cell layer. These results strongly suggest that the GnRH-3 neurons located in the terminal nerve area represent the source of GnRH-3 innervation in the retina of this species. In order to clarify whether the retina is a target for GnRH, the expression pattern of GnRH receptors (dlGnRHR) was also analyzed by RT-PCR and in situ hybridization. RT-PCR revealed the retinal expression of dlGnRHR-II-2b, -1a, -1b and -1c, while in situ hybridization only showed positive signals for the receptors dlGnRHR-II-2b and -1a. Finally, double-immunohistochemistry showed that GnRH-3 projections reaching the sea bass retina end in close proximity to tyrosine hydroxylase (dopaminergic) cells, which also expressed the dlGnRHR-II-2b receptor subtype. Taken together, these results suggest an important role for GnRH-3 in the modulation of dopaminergic cell activities and retinal functions in sea bass.
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Affiliation(s)
- Arianna Servili
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEIMAR), E-11510 Puerto Real, Spain
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25
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Yáñez J, Folgueira M, Köhler E, Martínez C, Anadón R. Connections of the terminal nerve and the olfactory system in two galeomorph sharks: an experimental study using a carbocyanine dye. J Comp Neurol 2012; 519:3202-17. [PMID: 21618231 DOI: 10.1002/cne.22674] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In elasmobranchs the terminal nerve courses separately from the olfactory nerve. This characteristic makes elasmobranchs excellent models to study the anatomy and function of these two systems. Here we study the neural connections of the terminal nerve and olfactory system in two sharks by experimental tracing methods using carbocyanine dyes. The main projections from the terminal nerve system (consisting of three ganglia in Scyliorhinus canicula) course ipsilaterally to the medial septal nucleus and bilaterally to the ventromedial telencephalic pallial region. Minor terminal nerve projections were also traced ipsilaterally to diencephalic and mesencephalic levels. With regard to the olfactory connections, our results show that in sharks, unlike ray-finned fishes, the primary olfactory projections are mainly restricted to the olfactory bulb. We also performed tracer application to the olfactory bulb in order to analyze the possible central neuroanatomical relationship between the projections of the terminal nerve and the olfactory bulb. In these experiments labeled neurons and fibers were observed from telencephalic to caudal mesencephalic regions. However, we observe almost no overlap between the two systems at central levels. The afferent and the putatively efferent connections of the dogfish olfactory bulb are compared with those previously reported in other elasmobranchs. The significance of the extratelencephalic secondary olfactory projections is also discussed in a comparative context.
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Affiliation(s)
- Julián Yáñez
- Department of Cell and Molecular Biology, University of A Coruña, E-15008 A Coruña, Spain.
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26
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Northcutt RG. Olfactory projections in the white sturgeon, Acipenser transmontanus: an experimental study. J Comp Neurol 2011; 519:1999-2022. [PMID: 21452220 DOI: 10.1002/cne.22619] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Telencephalic evolution in ray-finned fishes shows increasing complexity from polypteriform fishes through sturgeons to teleosts. Telencephalic organization in sturgeons is thus critical to our understanding of ray-finned fish evolution, but it is poorly understood, particularly as regards the roof or pallium. Two major hypotheses exist regarding the medial part of area dorsalis (Dm): that Dm is extended; and that Dm is restricted. The extent and topography of secondary olfactory projections to the pallium are critical in evaluating these hypotheses, but there is little agreement regarding these projections. Olfactory projections in the white sturgeon were therefore examined by using the carbocyanine probe DiI, biocytin, and biotinylated dextrin amine (BDA). Both DiI and BDA revealed primary olfactory projections to the olfactory bulb and primary extrabulbar projections widely in the telencephalon and to more restricted regions of the diencephalon. Myelinated secondary olfactory fibers caused DiI to be less effective in labeling secondary olfactory projections, which terminate in all subpallial nuclei and in the pallium: sparsely in the medial pallial division (Dm); heavily in the posterior pallial division (Dp); and more lightly in the lateral pallial division (Dl). In the diencephalon, substantial secondary olfactory projections were seen to the habenular nuclei, the rostral pole of the inferior lobe, and several nuclei of the posterior tubercle. All secondary olfactory projections were bilateral but heavier ipsilaterally. Bulbopetal neurons were located in both pallial and subpallial centers and were more numerous ipsilaterally. These results corroborate an earlier experimental study on the shovelnose sturgeon and indicate a restricted Dm in sturgeons.
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Affiliation(s)
- R Glenn Northcutt
- Laboratory of Comparative Neurobiology, Scripps Institution of Oceanography, La Jolla, California 92093, USA.
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27
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Kato T, Yamada Y, Yamamoto N. General visceral and gustatory connections of the posterior thalamic nucleus of goldfish. J Comp Neurol 2011; 519:3102-23. [DOI: 10.1002/cne.22669] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Wang X, Huang L, Li Y, Li X, Li P, Ray J, Li L. Characterization of GFP-tagged GnRH-containing terminalis neurons in transgenic zebrafish. J Cell Physiol 2011; 226:608-15. [PMID: 20717967 DOI: 10.1002/jcp.22369] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The terminalis nerve (TN) has been described in all vertebrate species, in which it plays important roles in animal behavior and physiology. In teleost fish, the TN is located in the olfactory bulb and in its nerve tract. Here, we report a study on the characterization of the TN cell development, axon projection and physiology in zebrafish (Danio rerio). We have generated several lines of transgenic zebrafish [Tg (GnRH-3::GFP)] that express GFP in the TN cells. The transgenes are expressed under the transcriptional control of the zebrafish GnRH-3 promoter. During development, the first GFP-positive TN cell was identified at approximately 34 h post-fertilization (hpf). By 38 hpf, several clusters of TN cells were identified in the olfactory bulb and olfactory nerve tract. In the olfactory bulb, the TN cells projected axons caudally. In the forebrain, some of the TN axons extended caudally, but most crossed the midline of the brain at the commissural anterior. In the midbrain, some of the TN axons extended dorsally towards the tectum, whereas other axons extended caudally, or extended ventrally to the optic nerve where they entered the neural retina. We also examined the cell membrane property of the TN cells. Using patch-clamp techniques, we recorded spontaneous and evoked action potentials from isolated TN cells. We examined the expression of glutamate receptors in the TN cells. The data shed light on the mechanisms of TN function in the nervous system and in the regulation of animal physiology.
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Affiliation(s)
- Xiaokai Wang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
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29
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ABE H, OKA Y. Mechanisms of Neuromodulation by a Nonhypophysiotropic GnRH System Controlling Motivation of Reproductive Behavior in the Teleost Brain. J Reprod Dev 2011; 57:665-74. [DOI: 10.1262/jrd.11-055e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hideki ABE
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yoshitaka OKA
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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30
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Kawai T, Abe H, Akazome Y, Oka Y. Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus. J Neurophysiol 2010; 104:3540-50. [DOI: 10.1152/jn.00639.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is well known as a hypophysiotropic hormone that is produced in the hypothalamus and facilitates the release of gonadotropins from the pituitary gonadotropes. On the other hand, the functions of extrahypothalamic GnRH systems still remain elusive. Here we examined whether the activity of the olfactory bulbar neural circuits is modulated by GnRH that originates mainly from the terminal nerve (TN) GnRH system in goldfish ( Carassius auratus). As the morphological basis, we first observed that goldfish TNs mainly express salmon GnRH (sGnRH) mRNA and that sGnRH-immunoreactive fibers are distributed in both the mitral and the granule cell layers. We then examined by extracellular recordings the effect of GnRH on the electrically evoked in vitro field potentials that arise from synaptic activities from mitral to granule cells. We found that GnRH enhances the amplitude of the field potentials. Furthermore, these effects were observed in both cases when the field potentials were evoked by stimulating either the lateral or the medial olfactory tract, conveying functionally different sensory information, separately, and suggesting that GnRH may modulate the responsiveness to wide categories of odorants in the olfactory bulb. Because GnRH also changed the paired-pulse ratio, it is suggested that the increased amplitude of the field potential results from changes in the presynaptic glutamate release of mitral cells rather than the increase in the glutamate receptor sensitivity of granule cells. These results suggest that TN regulates the olfactory responsiveness of animals appropriately by releasing sGnRH peptides in the olfactory bulbar neural circuits.
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Affiliation(s)
- Takafumi Kawai
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hideki Abe
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yasuhisa Akazome
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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Oka Y. Electrophysiological characteristics of gonadotrophin-releasing hormone 1-3 neurones: insights from a study of fish brains. J Neuroendocrinol 2010; 22:659-63. [PMID: 20646172 DOI: 10.1111/j.1365-2826.2010.02035.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The vertebrate gonadotrophin-releasing hormone (GnRH) neurones are considered to consist of one group of hypothalamic neuroendocrine and two groups of extrahypothalamic neuromodulatory GnRH neurones, and each group of neurones expresses different molecular species of GnRH peptide. Different GnRH peptides are produced by one of the three paralogous GnRH genes, gnrh1, gnrh2 and gnrh3, which are considered to have originated from gene duplications. All three GnRH systems are well developed in teleost brains. By taking advantage of this, and especially the use of GnRH-green fluorescent protein transgenic fish, the anatomical and electrophysiological properties of all three types of GnRH neurones can now be studied. The hypophysiotropic GnRH1 neurones in the preoptic area show episodic spontaneous electrical activities, whereas the extrahypothalamic GnRH2 neurones in the midbrain and GnRH3 neurones in the terminal nerve show regular intrinsic pacemaker activities. It is suggested that these different electrophysiological properties are related to their different functions (i.e. GnRH1 neurones act as hypophysiotropic neuroendocrine regulators and GnRH2 and GnRH3 neurones act as neuromodulators). The present review focuses on recent electrophysiological analyses of GnRH3 neurones, which have revealed the excitatory GABAergic and the inhibitory FMRFamide-like peptidergic regulations acting upon them, as well as gap junctional electrotonic coupling.
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Affiliation(s)
- Y Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
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32
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Yoshimoto M, Yamamoto N. Ascending general visceral sensory pathways from the brainstem to the forebrain in a cichlid fish, Oreochromis (Tilapia) niloticus. J Comp Neurol 2010; 518:3570-603. [DOI: 10.1002/cne.22415] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kawai T, Oka Y, Eisthen H. The role of the terminal nerve and GnRH in olfactory system neuromodulation. Zoolog Sci 2010; 26:669-80. [PMID: 19832678 DOI: 10.2108/zsj.26.669] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Animals must regulate their sensory responsiveness appropriately with respect to their internal and external environments, which is accomplished in part via centrifugal modulatory pathways. In the olfactory sensory system, responsiveness is regulated by neuromodulators released from centrifugal fibers into the olfactory epithelium and bulb. Among the modulators known to modulate neural activity of the olfactory system, one of the best understood is gonadotropin-releasing hormone (GnRH). This is because GnRH derives mainly from the terminal nerve (TN), and the TN-GnRH system has been suggested to function as a neuromodulator in wide areas of the brain, including the olfactory bulb. In the present article we examine the modulatory roles of the TN and GnRH in the olfactory epithelium and bulb as a model for understanding the ways in which olfactory responses can be tuned to the internal and external environments.
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Affiliation(s)
- Takafumi Kawai
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Nakane R, Oka Y. Excitatory action of GABA in the terminal nerve gonadotropin-releasing hormone neurons. J Neurophysiol 2010; 103:1375-84. [PMID: 20071623 DOI: 10.1152/jn.00910.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The terminal nerve (TN)-gonadotropin-releasing hormone (GnRH) neurons have been suggested to function as a neuromodulatory system that regulates the motivational and arousal state of the animal and have served as a model system for the study of GnRH neuron physiology. To investigate the synaptic control of the TN-GnRH neurons, we analyzed electrophysiologically the effect of GABA on the TN-GnRH neurons. GABA generally hyperpolarizes most of the neurons in the adult brain by activating GABA(A) receptors while the activation of GABA(A) receptors depolarizes some specific neurons in the mature brain. Here we examined the GABA(A) receptor-mediated responses in the TN-GnRH neurons of adult teleost fish, the dwarf gourami, by means of gramicidin-perforated patch-clamp and cell-attached patch-clamp recordings. The reversal potential for the currents through GABA(A) receptors under the voltage clamp was depolarized relative to the resting membrane potential. GABA(A) receptor activation depolarized TN-GnRH neurons under the current clamp and had excitatory effect on their electrical activity, whereas the stronger GABA(A) receptor activation had bidirectional effect (excitatory-inhibitory). This excitatory effect is suggested to arise from high [Cl(-)](i) and was shown to be suppressed by bumetanide, the blocker of Cl(-)-accumulating sodium-potassium-2-chloride co-transporter (NKCC). The present results demonstrate that GABA(A) receptor activation induces excitation in TN-GnRH neurons, which may facilitate their neuromodulatory functions by increasing their spontaneous firing frequencies. The excitatory actions of GABA in the adult brain have recently been attracting much attention, and the easily accessible large TN-GnRH neurons should be a nice model system to analyze their physiological functions.
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Affiliation(s)
- Ryo Nakane
- Dept. of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
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Reiner A. The Conservative Evolution of the Vertebrate Basal Ganglia. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/b978-0-12-374767-9.00002-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Ramakrishnan S, Wayne NL. Social cues from conspecifics alter electrical activity of gonadotropin-releasing hormone neurons in the terminal nerve via visual signals. Am J Physiol Regul Integr Comp Physiol 2009; 297:R135-41. [DOI: 10.1152/ajpregu.00143.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
There are multiple populations of gonadotropin-releasing hormone (GnRH) neurons in the brains of vertebrates. The population located in the hypothalamus/preoptic area is the best studied and is known to ultimately control reproduction. Teleost fish have an additional population of GnRH neurons in the terminal nerve (TN) associated with the olfactory bulbs, the physiological function of which is still unclear. Anatomical and physiological studies provide evidence that TN-GnRH neurons have extensive projections in the brain and modulate neuronal activity. Although there is anatomical evidence that the TN receives olfactory and optic sensory inputs, it is not known if sensory information is transmitted to TN-GnRH neurons to modulate their activity. In the present study, we tested the hypothesis that social cues from conspecifics modulate electrical activity of TN-GnRH neurons from the intact brain of female medaka fish ( Oryzias latipes). We further investigated the potential roles of chemosensory and visual signals in mediating the social cue response. We used a transgenic line of medaka with TN-GnRH neurons genetically tagged with green fluorescent protein, allowing visualization of specific neurons for whole-cell current clamp electrophysiology. We demonstrated that 24-h exposure to male visual and chemosensory cues suppressed the electrical activity of female TN-GnRH neurons compared with exposure to other females. Chemosensory cues alone were insufficient to induce this social cue response. However, visual cues alone replicated the “combined” social cue response. These findings support our hypothesis that sensory signals—and specifically, visual social cues—modulate electrical activity of TN-GnRH neurons.
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Abstract
A large skull is disadvantageous to animals that move quickly in three-dimensional space, such as fishes and birds in water or air. A cerebral neocortex with a six-layered sheet has not evolved, most likely due to the limited cranial space. Instead of the laminar cortex, telencephalic nuclear masses seem to have evolved as the pallium in teleost fishes. We consider that the nuclear masses contain rather simple neural circuits sharing a skeleton of simple circuits in the mammalian cortex, which have been elaborated by additional circuits in mammals. Such basic similarities at the connectional level shared by nuclear and cortical pallium might underlie similar or equivalent functions.
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Affiliation(s)
- Hironobu Ito
- Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo 113-8602, Japan.
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Repérant J, Médina M, Ward R, Miceli D, Kenigfest N, Rio J, Vesselkin N. The evolution of the centrifugal visual system of vertebrates. A cladistic analysis and new hypotheses. ACTA ACUST UNITED AC 2007; 53:161-97. [DOI: 10.1016/j.brainresrev.2006.08.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 08/10/2006] [Accepted: 08/21/2006] [Indexed: 12/23/2022]
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Mousley A, Polese G, Marks NJ, Eisthen HL. Terminal nerve-derived neuropeptide y modulates physiological responses in the olfactory epithelium of hungry axolotls (Ambystoma mexicanum). J Neurosci 2006; 26:7707-17. [PMID: 16855098 PMCID: PMC1855265 DOI: 10.1523/jneurosci.1977-06.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. Such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. The terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the olfactory epithelium, displays anatomical and neurochemical characteristics that suggest that it modulates activity in the olfactory epithelium. Using immunocytochemical techniques, we demonstrate that neuropeptide Y (NPY) is abundantly present in the terminal nerve in the axolotl (Ambystoma mexicanum), an aquatic salamander. Because NPY plays an important role in regulating appetite and hunger in many vertebrates, we investigated the possibility that NPY modulates activity in the olfactory epithelium in relation to the animal's hunger level. We therefore characterized the full-length NPY gene from axolotls to enable synthesis of authentic axolotl NPY for use in electrophysiological experiments. We find that axolotl NPY modulates olfactory epithelial responses evoked by l-glutamic acid, a food-related odorant, but only in hungry animals. Similarly, whole-cell patch-clamp recordings demonstrate that bath application of axolotl NPY enhances the magnitude of a tetrodotoxin-sensitive inward current, but only in hungry animals. These results suggest that expression or activity of NPY receptors in the olfactory epithelium may change with hunger level, and that terminal nerve-derived peptides modulate activity in the olfactory epithelium in response to an animal's changing behavioral and physiological circumstances.
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Repérant J, Ward R, Miceli D, Rio JP, Médina M, Kenigfest NB, Vesselkin NP. The centrifugal visual system of vertebrates: a comparative analysis of its functional anatomical organization. ACTA ACUST UNITED AC 2006; 52:1-57. [PMID: 16469387 DOI: 10.1016/j.brainresrev.2005.11.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 11/24/2005] [Accepted: 11/30/2005] [Indexed: 10/25/2022]
Abstract
The present review is a detailed survey of our present knowledge of the centrifugal visual system (CVS) of vertebrates. Over the last 20 years, the use of experimental hodological and immunocytochemical techniques has led to a considerable augmentation of this knowledge. Contrary to long-held belief, the CVS is not a unique property of birds but a constant component of the central nervous system which appears to exist in all vertebrate groups. However, it does not form a single homogeneous entity but shows a high degree of variation from one group to the next. Thus, depending on the group in question, the somata of retinopetal neurons can be located in the septo-preoptic terminal nerve complex, the ventral or dorsal thalamus, the pretectum, the optic tectum, the mesencephalic tegmentum, the dorsal isthmus, the raphé, or other rhombencephalic areas. The centrifugal visual fibers are unmyelinated or myelinated, and their number varies by a factor of 1000 (10 or fewer in man, 10,000 or more in the chicken). They generally form divergent terminals in the retina and rarely convergent ones. Their retinal targets also vary, being primarily amacrine cells with various morphological and neurochemical properties, occasionally interplexiform cells and displaced retinal ganglion cells, and more rarely orthotopic ganglion cells and bipolar cells. The neurochemical signature of the centrifugal visual neurons also varies both between and within groups: thus, several neuroactive substances used by these neurons have been identified; GABA, glutamate, aspartate, acetylcholine, serotonin, dopamine, histamine, nitric oxide, GnRH, FMRF-amide-like peptides, Substance P, NPY and met-enkephalin. In some cases, the retinopetal neurons form part of a feedback loop, relaying information from a primary visual center back to the retina, while in other, cases they do not. The evolutionary significance of this variation remains to be elucidated, and, while many attempts have been made to explain the functional role of the CVS, opinions vary as to the manner in which retinal activity is modified by this system.
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Affiliation(s)
- J Repérant
- CNRS UMR 5166, MNHN USM 0501, Département Régulation, Développement et Diversité Moléculaire du Muséum National d'Histoire Naturelle, C. P. 32, 7 rue Cuvier, 75231 Paris cedex 05, France.
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41
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Neuromodulatory Functions of Terminal Nerve‐GnRH Neurons. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1546-5098(06)25011-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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Xue HG, Yang CY, Ito H, Yamamoto N, Ozawa H. Primary and secondary sensory trigeminal projections in a cyprinid teleost, carp (Cyprinus carpio). J Comp Neurol 2006; 499:626-44. [PMID: 17029257 DOI: 10.1002/cne.21130] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Primary and secondary sensory trigeminal projections were studied by means of tract-tracing methods in a cyprinid teleost, the carp. Tracer injections into the trigeminal nerve root labeled terminals in the ipsilateral principal sensory trigeminal nucleus, descending trigeminal nucleus, medial funicular nucleus, facial lobe, and medial part of posterior lateral valvular nucleus. The principal sensory trigeminal nucleus is considered a major origin of the secondary sensory trigeminal projections in teleosts. To investigate the secondary sensory trigeminal projections, tracer injections were performed into the principal sensory trigeminal nucleus. The present study suggests that the principal sensory trigeminal nucleus projects to the bilateral ventromedial thalamic nucleus, periventricular pretectal nucleus, stratum album centrale of the optic tectum, caudomedial region of lateral preglomerular nucleus, ventrolateral nucleus of semicircular torus, medial part of rostral and posterior lateral valvular nucleus, oculomotor nucleus, trochlear nucleus, trigeminal motor nucleus, facial motor nucleus, superior and inferior reticular formation, descending trigeminal nucleus, medial funicular nucleus, inferior olive, and to the contralateral sensory trigeminal nucleus. These observations indicate that the primary and secondary trigeminal sensory projections of a cyprinid teleost, the carp, are similar to those in percomorph teleosts.
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Affiliation(s)
- Hao-Gang Xue
- Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo 113-8602, Japan.
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43
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Xue HG, Yamamoto N, Yang CY, Kerem G, Yoshimoto M, Sawai N, Ito H, Ozawa H. Projections of the sensory trigeminal nucleus in a percomorph teleost, tilapia (Oreochromis niloticus). J Comp Neurol 2006; 495:279-98. [PMID: 16440296 DOI: 10.1002/cne.20865] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The sensory trigeminal nucleus of teleosts is the rostralmost nucleus among the trigeminal sensory nuclear group in the rhombencephalon. The sensory trigeminal nucleus is known to receive the somatosensory afferents of the ophthalmic, maxillar, and mandibular nerves. However, the central connections of the sensory trigeminal nucleus remain unclear. Efferents of the sensory trigeminal nucleus were examined by means of tract-tracing methods, in a percomorph teleost, tilapia. After tracer injections to the sensory trigeminal nucleus, labeled terminals were seen bilaterally in the ventromedial thalamic nucleus, periventricular pretectal nucleus, medial part of preglomerular nucleus, stratum album centrale of the optic tectum, ventrolateral nucleus of the semicircular torus, lateral valvular nucleus, prethalamic nucleus, tegmentoterminal nucleus, and superior and inferior reticular formation, with preference for the contralateral side. Labeled terminals were also found bilaterally in the oculomotor nucleus, trochlear nucleus, trigeminal motor nucleus, facial motor nucleus, facial lobe, descending trigeminal nucleus, medial funicular nucleus, and contralateral sensory trigeminal nucleus and inferior olive. Labeled terminals in the oculomotor nucleus and trochlear nucleus showed similar densities on both sides of the brain. However, labelings in the trigeminal motor nucleus, facial motor nucleus, facial lobe, descending trigeminal nucleus, and medial funicular nucleus showed a clear ipsilateral dominance. Reciprocal tracer injection experiments to the ventromedial thalamic nucleus, optic tectum, and semicircular torus resulted in labeled cell bodies in the sensory trigeminal nucleus, with a few also in the descending trigeminal nucleus.
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Affiliation(s)
- Hao-Gang Xue
- Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo 113-8602, Japan.
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Huesa G, Anadón R, Yáñez J. Topography and connections of the telencephalon in a chondrostean,Acipenser baeri: An experimental study. J Comp Neurol 2006; 497:519-41. [PMID: 16739163 DOI: 10.1002/cne.20977] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sturgeons belong to an ancient group of the extant actinopterygian fishes. Accordingly, the study of their brain connections is important to understand brain evolution in the line leading to teleosts. We examined the topography and connections of the various telencephalic regions of the Siberian sturgeon (Acipenser baeri). The telencephalic regions were characterized on the basis of acetylcholinesterase histochemistry and calbindin-D28k and calretinin immunohistochemistry. The telencephalic connections were investigated by using the fluorescent dye DiI (1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate) in fixed brains. Application of DiI to different areas of the pallial (dorsal) regions of the telencephalic lobes showed that they have mostly intratelencephalic connections. A posterior pallial region is characterized by its similar hodology to that of the posterior zone of the teleosts dorsal telencephalon and those described in other ancient groups. Extratelencephalic connections of the pallium are scarce, although a few afferent and efferent connections with the diencephalon, mesencephalon, and rostral rhombencephalon were observed. DiI application to subpallial regions showed both intratelencephalic connections and connections with different brain regions. Afferents to the subpallium originate from the olfactory bulbs, preoptic area, thalamus, posterior tuberculum, hypothalamus, secondary gustatory nucleus, and raphe nuclei. Some of these connections are quite similar to those described for other vertebrates.
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Affiliation(s)
- Gema Huesa
- Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, 15071-A Coruña, Spain
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Deguchi T, Suwa H, Yoshimoto M, Kondoh H, Yamamoto N. Central Connection of the Optic, Oculomotor, Trochlear and Abducens Nerves in Medaka, Oryzias latipes. Zoolog Sci 2005; 22:321-32. [PMID: 15795495 DOI: 10.2108/zsj.22.321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Medaka (Oryzias latipes) is one of the few vertebrate experimental animals in which inbred lines have been established. It is also a species that has advanced in genetic studies in a manner comparable to zebrafish. This fish is therefore a good model for studying functional organization of the nervous system, but anatomical analysis of its nervous system has been limited to embryonic stages. In the present study, we investigated anatomy of cranial nerves in adult fish focusing on the visual function, using an inbred strain of medaka. Cranial nerves of medaka were labeled using biocytin, revealing a central distribution of retinofugal terminals, retinopetal neurons, and oculomotor, trochlear and abducens motor neurons. The optic nerve of the adult medaka was of a complete decussation type. Retinofugal terminals were located in 8 brain nuclei, the suprachiasmatic nucleus, nucleus pretectalis superficialis, nucleus dorsolateralis thalami, area pretectalis pars dorsalis (APd), area pretectalis pars ventralis (APv), nucleus of the posterior commissure (NPC), accessory optic nucleus, and the tectum opticum. Retinopetal neurons were identified in 6 brain nuclei, the ganglion of the terminal nerve, preoptic retinopetal nucleus, nucleus dorsolateralis thalami, APd, APv, and NPC. The oculomotor neurons were mostly labeled ipsilaterally and were located dorsomedially, abutting the fasciculus longitudinalis medialis in the mesencephalon. The trochlear nucleus was located contralaterally and dorsolaterally adjacent to the fasciculus longitudinalis medialis in the mesencephalon. The abducens nucleus was located ipsilaterally in a ventrolateral part of the rhombencephalic reticular formation. These results, generally similar to those in other teleosts, provide the basis for future behavioral and genetic studies in medaka.
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Affiliation(s)
- Tomonori Deguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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Yamamoto N, Ito H. Fiber connections of the anterior preglomerular nucleus in cyprinids with notes on telencephalic connections of the preglomerular complex. J Comp Neurol 2005; 491:212-33. [PMID: 16134137 DOI: 10.1002/cne.20681] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fiber connections of the anterior preglomerular nucleus (PGa) were studied in carp and goldfish by tracer injection experiments to the nucleus and telencephalon. The PGa received fibers from the central nucleus of semicircular torus, perilemniscular nucleus, anterior tuberal nucleus, and medial pretoral nucleus, all of which are presumed auditory structures. The PGa projected to the dorsal (dDm) and ventral (vDm) regions of medial part of dorsal telencephalic area. The caudomedial region of lateral preglomerular nucleus (PGl) and medial zone of medial preglomerular nucleus (PGm), which also receive auditory toral fibers, projected to the same telencephalic regions as did PGa. These preglomerular structures and the PGa also received in common descending fibers from a rostromedial portion of dDm. The PGa also received fibers from the parvocellular and magnocellular preoptic nuclei, and suprachiasmatic nucleus and projected to the anterior tuberal nucleus and medial inferior lobe, suggesting neurohormonal and circadian control on the PGa and auditory influences on hypothalamic functions. Of other diencephalic nuclei that receive auditory toral fibers, only small numbers of neurons were labeled in the central posterior thalamic nucleus and anterior tuberal nucleus even after large injections to the dorsal telencephalic area. Thus, the PGa and closely related preglomerular regions, not the dorsal thalamus, appear to constitute the major auditory relay station to the dorsal telencephalic area. The rostrolateral region of PGl, rostral and lateral zones of PGm, commissural preglomerular nucleus, and preglomerular tertiary gustatory nucleus, which do not receive auditory toral fibers, also projected to the dorsal telencephalic area.
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Affiliation(s)
- Naoyuki Yamamoto
- Department of Anatomy and Laboratory for Comparative Neuromorphology, Nippon Medical School, Tokyo 113-8602, Japan.
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47
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Folgueira M, Anadón R, Yáñez J. Experimental study of the connections of the telencephalon in the rainbow trout (Oncorhynchus mykiss). II: Dorsal area and preoptic region. J Comp Neurol 2004; 480:204-33. [PMID: 15514931 DOI: 10.1002/cne.20341] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study and the accompanying article (Folgueira et al., 2004a), the fluorescent carbocyanine dye 1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was used in fixed tissue to comprehensively analyze the connections of the different regions of the telencephalic lobes and the preoptic region of the rainbow trout. Here, we analyze the connections of the dorsal area (D; pallium) of the telencephalon, and the preoptic region, as well as the telencephalic connections of several structures in the diencephalon and brainstem of juvenile trout. The dorsal plus dorsolateral pallial zone of D (Dd+Dl-d) receives afferents from contralateral Dd+Dl-d, the ventral area of the telencephalon, preoptic nucleus, suprachiasmatic nucleus, medial thalamus, preglomerular complex, anterior and lateral tuberal nuclei, posterior tuberal nucleus, posterior hypothalamic lobe, superior raphe nucleus, and the rhombencephalic central gray and reticular formation, and projects to the central zone of D (Dc), medial thalamus, and some caudomedial hypothalamic regions. The medial zone of D (Dm) maintains reciprocal connections with the preglomerular complex and also receives afferents from the preoptic nucleus, suprachiasmatic nucleus, anterior tuberal nucleus, preglomerular tertiary gustatory nucleus, posterior tubercle, superior raphe nucleus, locus coeruleus, and the rhombencephalic central gray, and reticular formation. Dc receives fibers mainly from Dd+Dl-d, preoptic nucleus, preglomerular complex, and torus semicircularis and projects to several extratelencephalic centers, including the paracommissural nucleus, optic tectum, torus semicircularis, thalamus, preglomerular complex, posterior tubercle nuclei, and inferior hypothalamic lobes. The posterior zone of D (Dp) is mainly connected with the olfactory bulbs, the ventral and supracommissural nuclei of the ventral area (subpallium), the preoptic nucleus, and the preglomerular complex and projects to wide hypothalamic and posterior tubercular regions. The preoptic nucleus projects to the olfactory bulb, to most regions of the telencephalic lobes, and to several diencephalic and brainstem structures. These results reveal complex and specialized connectional patterns in the rainbow trout dorsal telencephalon and preoptic region. Most of these connections have not been described previously in salmonids. These connections indicate that the salmonid telencephalon is involved in multisensorial processing and modulation of brain activity.
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Affiliation(s)
- Mónica Folgueira
- Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, 15071 A Coruña, Spain
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Folgueira M, Anadón R, Yáñez J. An experimental study of the connections of the telencephalon in the rainbow trout (Oncorhynchus mykiss). I: Olfactory bulb and ventral area. J Comp Neurol 2004; 480:180-203. [PMID: 15514934 DOI: 10.1002/cne.20340] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The fluorescent carbocyanine dye 1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was used in fixed tissue to comprehensively analyze the connections of the olfactory bulbs and the different regions of the ventral (V) area of the telencephalic lobes (subpallium) of the rainbow trout. With this goal, DiI was applied to the different telencephalic nuclei and zones, as well as to the olfactory nerve, the olfactory bulb, the retina, and to several structures in the diencephalon and brainstem of juvenile trout. The olfactory bulbs maintain reciprocal connections with several regions of the telencephalon [ventral nucleus of V (Vv), supracommissural nucleus (Vs), posterior zone of D (Dp), preoptic nucleus], and also project to the diencephalon (posterior tuberal nucleus, posterior hypothalamic lobe). Vv receives afferents from Vs, the dorsal nucleus of V (Vd), the preoptic nucleus, and from several nuclei in the diencephalon and brainstem (suprachiasmatic nucleus, anterior and lateral tuberal nuclei, preglomerular complex, tertiary gustatory nucleus, posterior tubercle, inferior hypothalamic lobes, thalamus, torus semicircularis, secondary gustatory nucleus, locus coeruleus, superior raphe nucleus, central gray, and reticular formation), and projects to dorsal (pallial) regions and most of the nuclei afferent to Vv. The dorsal nucleus of V (Vd) and Vs mainly project to the dorsal area. In an accompanying article (Folgueira et al., 2004), we present the results of application of DiI to dorsal (pallial) telencephalic regions, as well as of several experiments of tracer application to extratelencephalic regions. The results presented here, together with those of the accompanying article, reveal a complex connectional pattern of the rainbow trout ventral telencephalon, most of these connections having not been described previously in salmonids.
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Affiliation(s)
- Mónica Folgueira
- Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, 15071 A Coruña, Spain
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Médina M, Repérant J, Ward R, Miceli D. Presumptive FMRF-amide-like immunoreactive retinopetal fibres in Crocodylus niloticus. Brain Res 2004; 1025:231-6. [PMID: 15464765 DOI: 10.1016/j.brainres.2004.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2004] [Indexed: 10/26/2022]
Abstract
A small contingent of 30-50 of centrifugal visual fibres, showing FMRF-amide-like immunoreactivity, has been identified in C. niloticus; these fibres extend from the chiasmatic region into the retina. They do not take the marginal optic tract, but pass medially to the chiasmatic fascicles, from the preoptic region. The cells of origin of these fibres have not been identified. However, none of the retinopetal neurons of the brainstem [M. Medina, J. Reperant, R. Ward, D. Miceli, Centrifugal visual system of Crocodylus niloticus : a hodological, histochemical and immunocytochemical study, J. Comp. Neurol. 468 (2004) 65-85], labelled by retrograde transport of rhodamine beta-isothiocyanate after intraocular injection of this tracer, show FMRF-amide-like immunoreactivity; neither are any of the FMRF-amide-like immunopositive neurons in the crocodile brain, particularly those of the complex involving the terminal nerve and the septo-preoptic region, labelled by rhodamine after its intraocular injection.
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Affiliation(s)
- Monique Médina
- Laboratoire d'Anatomie Comparée, Muséum National d'Histoire Naturelle, Département Ecologie et Gestion de la Biodiversité, CNRS FRE2696-MNHN USM0302 CP 55, 55 rue Buffon, F-75005 Paris, France.
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Rink E, Wullimann MF. Connections of the ventral telencephalon (subpallium) in the zebrafish (Danio rerio). Brain Res 2004; 1011:206-20. [PMID: 15157807 DOI: 10.1016/j.brainres.2004.03.027] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2004] [Indexed: 11/27/2022]
Abstract
Connections of the medial precommissural subpallial ventral telencephalon, i.e., dorsal (Vd, interpreted as part of striatum) and ventral (Vv, interpreted as part of septum) nuclei of area ventralis telencephali, were studied in the zebrafish (Danio rerio) using two tracer substances (DiI or biocytin). The following major afferent nuclei to Vd/Vv were identified: medial and posterior pallial zones of dorsal telencephalic area, and the subpallial supracommissural and postcommissural nuclei of the ventral telencephalic area, the olfactory bulb, dorsal entopeduncular, anterior and posterior parvocellular preoptic and suprachiasmatic nuclei, anterior, dorsal and central posterior dorsal thalamic, as well as rostrolateral nuclei, periventricular nucleus of the posterior tuberculum, posterior tuberal nucleus, various tuberal hypothalamic nuclei, dorsal tegmental nucleus, superior reticular nucleus, locus coeruleus, and superior raphe nucleus. Efferent projections of the ventral telencephalon terminate in the supracommissural nucleus of area ventralis telencephali, the posterior zone of area dorsalis telencephali, habenula, periventricular pretectum, paracommissural nucleus, posterior dorsal thalamus, preoptic region, midline posterior tuberculum (especially the area dorsal to the posterior tuberal nucleus), tuberal (midline) hypothalamus and interpeduncular nucleus. Strong reciprocal interconnections likely exist between septum and preoptic region/midline hypothalamus and between striatum and dorsal thalamus (dopaminergic) posterior tuberculum. Regarding ascending activating/modulatory systems, the pallium shares with the subpallium inputs from the (noradrenergic) locus coeruleus, and the (serotoninergic) superior raphe, while the subpallium additionally receives such inputs from the (dopaminergic) posterior tuberculum, the (putative cholinergic) superior reticular nucleus, and the (putative histaminergic) caudal hypothamalic zone.
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Affiliation(s)
- Elke Rink
- Brain Research Institute, University of Bremen, 28334, Bremen, Germany.
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