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Trebels B, Dippel S, Anders J, Ernst C, Goetz B, Keyser T, Rexer KH, Wimmer EA, Schachtner J. Anatomic and neurochemical analysis of the palpal olfactory system in the red flour beetle Tribolium castaneum, HERBST. Front Cell Neurosci 2023; 17:1097462. [PMID: 36998268 PMCID: PMC10043995 DOI: 10.3389/fncel.2023.1097462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 01/30/2023] [Indexed: 02/25/2023] Open
Abstract
The paired antennal lobes were long considered the sole primary processing centers of the olfactory pathway in holometabolous insects receiving input from the olfactory sensory neurons of the antennae and mouthparts. In hemimetabolous insects, however, olfactory cues of the antennae and palps are processed separately. For the holometabolous red flour beetle Tribolium castaneum, we could show that primary processing of the palpal and antennal olfactory input also occurs separately and at distinct neuronal centers. While the antennal olfactory sensory neurons project into the antennal lobes, those of the palps project into the paired glomerular lobes and the unpaired gnathal olfactory center. Here we provide an extended analysis of the palpal olfactory pathway by combining scanning electron micrographs with confocal imaging of immunohistochemical staining and reporter expression identifying chemosensory and odorant receptor-expressing neurons in the palpal sensilla. In addition, we extended the anatomical characterization of the gnathal olfactory center by 3D reconstructions and investigated the distribution of several neuromediators. The similarities in the neuromediator repertoire between antennal lobes, glomerular lobes, and gnathal olfactory center underline the role of the latter two as additional primary olfactory processing centers.
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Affiliation(s)
- Björn Trebels
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
| | - Stefan Dippel
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Janet Anders
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Clara Ernst
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Brigitte Goetz
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Tim Keyser
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Karl Heinz Rexer
- Biodiversity of Plants, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Ernst A. Wimmer
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Georg-August-University Göttingen, Göttingen, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
| | - Joachim Schachtner
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
- Clausthal University of Technology, Clausthal-Zellerfeld, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
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Arnold T, Korek S, Massah A, Eschstruth D, Stengl M. Candidates for photic entrainment pathways to the circadian clock via optic lobe neuropils in the Madeira cockroach. J Comp Neurol 2020; 528:1754-1774. [PMID: 31860126 DOI: 10.1002/cne.24844] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 12/09/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022]
Abstract
The compound eye of cockroaches is obligatory for entrainment of the Madeira cockroach's circadian clock, but the cellular nature of its entrainment pathways is enigmatic. Employing multiple-label immunocytochemistry, histochemistry, and backfills, we searched for photic entrainment pathways to the accessory medulla (AME), the circadian clock of the Madeira cockroach. We wanted to know whether photoreceptor terminals could directly contact pigment-dispersing factor-immunoreactive (PDF-ir) circadian pacemaker neurons with somata in the lamina (PDFLAs) or somata next to the AME (PDFMEs). Short green-sensitive photoreceptor neurons of the compound eye terminated in lamina layers LA1 and LA2, adjacent to PDFLAs and PDFMEs that branched in LA3. Long UV-sensitive compound eye photoreceptor neurons terminated in medulla layer ME2 without direct contact to ipsilateral PDFMEs that arborized in ME4. Multiple neuropeptide-ir interneurons branched in ME4, connecting the AME to ME2. Before, extraocular photoreceptors of the lamina organ were suggested to send terminals to accessory laminae. There, they overlapped with PDFLAs that mostly colocalized PDF, FMRFamide, and 5-HT immunoreactivities, and with terminals of ipsi- and contralateral PDFMEs. We hypothesize that during the day cholinergic activation of the largest PDFME via lamina organ photoreceptors maintains PDF release orchestrating phases of sleep-wake cycles. As ipsilateral PDFMEs express excitatory and contralateral PDFMEs inhibitory PDF autoreceptors, diurnal PDF release keeps both PDF-dependent clock circuits in antiphase. Future experiments will test whether ipsilateral PDFMEs are sleep-promoting morning cells, while contralateral PDFMEs are activity-promoting evening cells, maintaining stable antiphase via the largest PDFME entrained by extraocular photoreceptors of the lamina organ.
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Affiliation(s)
- Thordis Arnold
- FB 10, Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Sebastian Korek
- FB 10, Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Azar Massah
- FB 10, Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - David Eschstruth
- FB 10, Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
| | - Monika Stengl
- FB 10, Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
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von Hadeln J, Hensgen R, Bockhorst T, Rosner R, Heidasch R, Pegel U, Quintero Pérez M, Homberg U. Neuroarchitecture of the central complex of the desert locust: Tangential neurons. J Comp Neurol 2019; 528:906-934. [PMID: 31625611 DOI: 10.1002/cne.24796] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/11/2022]
Abstract
The central complex (CX) comprises a group of midline neuropils in the insect brain, consisting of the protocerebral bridge (PB), the upper (CBU) and lower division (CBL) of the central body and a pair of globular noduli. It receives prominent input from the visual system and plays a major role in spatial orientation of the animals. Vertical slices and horizontal layers of the CX are formed by columnar, tangential, and pontine neurons. While pontine and columnar neurons have been analyzed in detail, especially in the fruit fly and desert locust, understanding of the organization of tangential cells is still rudimentary. As a basis for future functional studies, we have studied the morphologies of tangential neurons of the CX of the desert locust Schistocerca gregaria. Intracellular dye injections revealed 43 different types of tangential neuron, 8 of the PB, 5 of the CBL, 24 of the CBU, 2 of the noduli, and 4 innervating multiple substructures. Cell bodies of these neurons were located in 11 different clusters in the cell body rind. Judging from the presence of fine versus beaded terminals, the vast majority of these neurons provide input into the CX, especially from the lateral complex (LX), the superior protocerebrum, the posterior slope, and other surrounding brain areas, but not directly from the mushroom bodies. Connections are largely subunit- and partly layer-specific. No direct connections were found between the CBU and the CBL. Instead, both subdivisions are connected in parallel with the PB and distinct layers of the noduli.
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Affiliation(s)
- Joss von Hadeln
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Ronja Hensgen
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Tobias Bockhorst
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Ronny Rosner
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Ronny Heidasch
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Uta Pegel
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Manuel Quintero Pérez
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, and Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
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Evolutionarily conserved anatomical and physiological properties of olfactory pathway through fourth-order neurons in a species of grasshopper (Hieroglyphus banian). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:813-838. [DOI: 10.1007/s00359-019-01369-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 08/08/2019] [Accepted: 09/04/2019] [Indexed: 01/18/2023]
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Nässel DR, Zandawala M. Recent advances in neuropeptide signaling in Drosophila, from genes to physiology and behavior. Prog Neurobiol 2019; 179:101607. [PMID: 30905728 DOI: 10.1016/j.pneurobio.2019.02.003] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/18/2019] [Accepted: 02/28/2019] [Indexed: 12/11/2022]
Abstract
This review focuses on neuropeptides and peptide hormones, the largest and most diverse class of neuroactive substances, known in Drosophila and other animals to play roles in almost all aspects of daily life, as w;1;ell as in developmental processes. We provide an update on novel neuropeptides and receptors identified in the last decade, and highlight progress in analysis of neuropeptide signaling in Drosophila. Especially exciting is the huge amount of work published on novel functions of neuropeptides and peptide hormones in Drosophila, largely due to the rapid developments of powerful genetic methods, imaging techniques and innovative assays. We critically discuss the roles of peptides in olfaction, taste, foraging, feeding, clock function/sleep, aggression, mating/reproduction, learning and other behaviors, as well as in regulation of development, growth, metabolic and water homeostasis, stress responses, fecundity, and lifespan. We furthermore provide novel information on neuropeptide distribution and organization of peptidergic systems, as well as the phylogenetic relations between Drosophila neuropeptides and those of other phyla, including mammals. As will be shown, neuropeptide signaling is phylogenetically ancient, and not only are the structures of the peptides, precursors and receptors conserved over evolution, but also many functions of neuropeptide signaling in physiology and behavior.
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Affiliation(s)
- Dick R Nässel
- Department of Zoology, Stockholm University, Stockholm, Sweden.
| | - Meet Zandawala
- Department of Zoology, Stockholm University, Stockholm, Sweden; Department of Neuroscience, Brown University, Providence, RI, USA.
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6
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von Hadeln J, Althaus V, Häger L, Homberg U. Anatomical organization of the cerebrum of the desert locust Schistocerca gregaria. Cell Tissue Res 2018; 374:39-62. [DOI: 10.1007/s00441-018-2844-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 04/17/2018] [Indexed: 11/27/2022]
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Rosner R, von Hadeln J, Salden T, Homberg U. Anatomy of the lobula complex in the brain of the praying mantis compared to the lobula complexes of the locust and cockroach. J Comp Neurol 2017; 525:2343-2357. [PMID: 28295329 PMCID: PMC5435961 DOI: 10.1002/cne.24208] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/30/2022]
Abstract
The praying mantis is an insect which relies on vision for capturing prey, avoiding being eaten and for spatial orientation. It is well known for its ability to use stereopsis for estimating the distance of objects. The neuronal substrate mediating visually driven behaviors, however, is not very well investigated. To provide a basis for future functional studies, we analyzed the anatomical organization of visual neuropils in the brain of the praying mantis Hierodula membranacea and provide supporting evidence from a second species, Rhombodera basalis, with particular focus on the lobula complex (LOX). Neuropils were three‐dimensionally reconstructed from synapsin‐immunostained whole mount brains. The neuropil organization and the pattern of γ‐aminobutyric acid immunostaining of the medulla and LOX were compared between the praying mantis and two related polyneopteran species, the Madeira cockroach and the desert locust. The investigated visual neuropils of the praying mantis are highly structured. Unlike in most insects the LOX of the praying mantis consists of five nested neuropils with at least one neuropil not present in the cockroach or locust. Overall, the mantis LOX is more similar to the LOX of the locust than the more closely related cockroach suggesting that the sensory ecology plays a stronger role than the phylogenetic distance of the three species in structuring this center of visual information processing.
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Affiliation(s)
- Ronny Rosner
- Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Joss von Hadeln
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
| | - Tobias Salden
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
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Schmitt F, Vanselow JT, Schlosser A, Wegener C, Rössler W. Neuropeptides in the desert antCataglyphis fortis: Mass spectrometric analysis, localization, and age-related changes. J Comp Neurol 2016; 525:901-918. [DOI: 10.1002/cne.24109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/10/2016] [Accepted: 08/24/2016] [Indexed: 02/04/2023]
Affiliation(s)
- Franziska Schmitt
- Behavioral Physiology and Sociobiology, Theodor-Boveri-Institute, Biocenter; University of Würzburg; D-97074 Würzburg Germany
| | - Jens T. Vanselow
- Rudolf Virchow Center for Experimental Biomedicine; University of Würzburg; D-97080 Würzburg Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine; University of Würzburg; D-97080 Würzburg Germany
| | - Christian Wegener
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; D-97074 Würzburg Germany
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology, Theodor-Boveri-Institute, Biocenter; University of Würzburg; D-97074 Würzburg Germany
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9
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Fusca D, Schachtner J, Kloppenburg P. Colocalization of allatotropin and tachykinin-related peptides with classical transmitters in physiologically distinct subtypes of olfactory local interneurons in the cockroach (Periplaneta americana). J Comp Neurol 2015; 523:1569-86. [PMID: 25678036 DOI: 10.1002/cne.23757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 01/28/2015] [Accepted: 02/03/2015] [Indexed: 11/06/2022]
Abstract
In the insect antennal lobe different types of local interneurons mediate complex excitatory and inhibitory interactions between the glomerular pathways to structure the spatiotemporal representation of odors. Mass spectrometric and immunohistochemical studies have shown that in local interneurons classical neurotransmitters are likely to colocalize with a variety of substances that can potentially act as cotransmitters or neuromodulators. In the antennal lobe of the cockroach Periplaneta americana, gamma-aminobutyric acid (GABA) has been identified as the potential inhibitory transmitter of spiking type I local interneurons, whereas acetylcholine is most likely the excitatory transmitter of nonspiking type IIa1 local interneurons. This study used whole-cell patch clamp recordings combined with single-cell labeling and immunohistochemistry to test if the GABAergic type I local interneurons and the cholinergic type IIa1 local interneurons express allatotropin and tachykinin-related neuropeptides (TKRPs). These are two of the most abundant types of peptides in the insect antennal lobe. GABA-like and choline acetyltransferase (ChAT)-like immunoreactivity were used as markers for GABAergic and cholinergic neurons, respectively. About 50% of the GABA-like immunoreactive (-lir) spiking type I local interneurons were allatotropin-lir, and ∼ 40% of these neurons were TKRP-lir. About 20% of nonspiking ChAT-lir type IIa1 local interneurons were TKRP-lir. Our results suggest that in subpopulations of GABAergic and cholinergic local interneurons, allatotropin and TKRPs might act as cotransmitters or neuromodulators. To unequivocally assign neurotransmitters, cotransmitters, and neuromodulators to identified classes of antennal lobe neurons is an important step to deepen our understanding of information processing in the insect olfactory system.
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Affiliation(s)
- Debora Fusca
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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10
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Lismont E, Vleugels R, Marchal E, Badisco L, Van Wielendaele P, Lenaerts C, Zels S, Tobe SS, Vanden Broeck J, Verlinden H. Molecular cloning and characterization of the allatotropin precursor and receptor in the desert locust, Schistocerca gregaria. Front Neurosci 2015; 9:84. [PMID: 25814925 PMCID: PMC4357254 DOI: 10.3389/fnins.2015.00084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/25/2015] [Indexed: 12/25/2022] Open
Abstract
Allatotropins (ATs) are pleiotropic neuropeptides initially isolated from the tobacco hornworm, Manduca sexta. In 2008, the first receptor for AT-like peptides (ATR) was characterized in Bombyx mori. Since then, ATRs have also been characterized in M. sexta, Tribolium castaneum, Aedes aegypti and Bombus terrestris. These receptors show sequence similarity to vertebrate orexin (ORX) receptors. When generating an EST-database of the desert locust (Schistocerca gregaria) central nervous system, we found cDNA sequences encoding the Schgr-AT precursor and a fragment of its putative receptor. This receptor cDNA has now been completed and functionally expressed in mammalian cell lines. Activation of this receptor, designated as Schgr-ATR, by Schgr-AT caused an increase in intracellular calcium ions, as well as cyclic AMP (cAMP), with an EC50 value in the nanomolar range. In addition, the transcript distribution of both the Schgr-AT precursor and Schgr-ATR was investigated by means of quantitative real-time PCR. Moreover, we found more evidence for the myotropic and allatostimulatory actions of Schgr-AT in the desert locust. These data are discussed and situated in a broader context by comparison with literature data on AT and ATR in insects.
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Affiliation(s)
- Els Lismont
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | - Rut Vleugels
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | - Elisabeth Marchal
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium ; Department of Cell and Systems Biology, University of Toronto Toronto, ON, Canada
| | - Liesbeth Badisco
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | | | - Cynthia Lenaerts
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | - Sven Zels
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | - Stephen S Tobe
- Department of Cell and Systems Biology, University of Toronto Toronto, ON, Canada
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
| | - Heleen Verlinden
- Molecular Developmental Physiology and Signal Transduction, KU Leuven Leuven, Belgium
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11
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Beetz MJ, El Jundi B, Heinze S, Homberg U. Topographic organization and possible function of the posterior optic tubercles in the brain of the desert locust Schistocerca gregaria. J Comp Neurol 2015; 523:1589-607. [PMID: 25557150 DOI: 10.1002/cne.23736] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/23/2014] [Accepted: 12/23/2014] [Indexed: 01/01/2023]
Abstract
Migrating desert locusts, Schistocerca gregaria, are able to use the skylight polarization pattern for navigation. They detect polarized light with a specialized dorsal rim area in their compound eye. After multistage processing, polarization signals are transferred to the central complex, a midline-spanning brain area involved in locomotor control. Polarization-sensitive tangential neurons (TB-neurons) of the protocerebral bridge, a part of the central complex, give rise to a topographic arrangement of preferred polarization angles in the bridge, suggesting that the central complex acts as an internal sky compass. TB-neurons connect the protocerebral bridge with two adjacent brain areas, the posterior optic tubercles. To analyze the polarotopic organization of the central complex further, we investigated the number and morphologies of TB-neurons and the presence and colocalization of three neuroactive substances in these neurons. Triple immunostaining with antisera against Diploptera punctata allatostatin (Dip-AST), Manduca sexta allatotropin (Mas-AT), and serotonin (5HT) raised in the same host species revealed three spatially distinct TB-neuron clusters, each consisting of 10 neurons per hemisphere: cluster 1 and 3 showed Dip-AST/5HT immunostaining, whereas cluster 2 showed Dip-AST/Mas-AT immunostaining. Five subtypes of TB-neuron could be distinguished based on ramification patterns. Corresponding to ramification domains in the protocerebral bridge, the neurons invaded distinct but overlapping layers within the posterior optic tubercle. Similarly, neurons interconnecting the tubercles of the two hemispheres also targeted distinct layers of these neuropils. From these data we propose a neuronal circuit that may be suited to stabilize the internal sky compass in the central complex of the locust.
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Affiliation(s)
- M Jerome Beetz
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Basil El Jundi
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Stanley Heinze
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
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12
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Binzer M, Heuer CM, Kollmann M, Kahnt J, Hauser F, Grimmelikhuijzen CJP, Schachtner J. Neuropeptidome of Tribolium castaneum antennal lobes and mushroom bodies. J Comp Neurol 2014; 522:337-57. [PMID: 23818034 DOI: 10.1002/cne.23399] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 05/27/2013] [Accepted: 06/19/2013] [Indexed: 11/08/2022]
Abstract
Neuropeptides are a highly diverse group of signaling molecules that affect a broad range of biological processes in insects, including development, metabolism, behavior, and reproduction. In the central nervous system, neuropeptides are usually considered to act as neuromodulators and cotransmitters that modify the effect of "classical" transmitters at the synapse. The present study analyzes the neuropeptide repertoire of higher cerebral neuropils in the brain of the red flour beetle Tribolium castaneum. We focus on two integrative neuropils of the olfactory pathway, the antennal lobes and the mushroom bodies. Using the technique of direct peptide profiling by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we demonstrate that these neuropils can be characterized by their specific neuropeptide expression profiles. Complementary immunohistological analyses of selected neuropeptides revealed neuropeptide distribution patterns within the antennal lobes and the mushroom bodies. Both approaches revealed consistent differences between the neuropils, underlining that direct peptide profiling by mass spectrometry is a fast and reliable method to identify neuropeptide content.
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Affiliation(s)
- Marlene Binzer
- Philipps-University Marburg, Department of Biology, Animal Physiology, 35043, Marburg, Germany
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13
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Masood M, Orchard I. Molecular characterization and possible biological roles of allatotropin in Rhodnius prolixus. Peptides 2014; 53:159-71. [PMID: 24177575 DOI: 10.1016/j.peptides.2013.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 11/28/2022]
Abstract
Allatotropins (ATs) are a family of neuropeptides that have been shown to stimulate the biosynthesis of juvenile hormone in certain insect species, and to have stimulatory activity on some visceral muscles. Here, we have examined the AT in Rhodnius prolixus. Molecular analysis revealed a cDNA fragment of 973 bp encoding one mature amidated AT (Rhopr-AT) with transcript levels observed in the central nervous system (CNS) and pool of fat body, trachea and associated peripheral nerves. AT-like immunoreactive neurons were found throughout the CNS and AT-like immunoreactive processes were present on some peripheral tissues. Bioassays based upon changes in hindgut and dorsal vessel contractions failed to demonstrate any myotropic effects of Rhopr-AT on these tissues; however Rhopr-AT stimulated contractions of muscles surrounding the salivary glands and secretion of saliva, as judged by the reduction in content of the cherry red saliva from the salivary glands. Serotonin stimulated an increase in peristaltic contractions of the gland though no secretion was observed. Co-application of Rhopr-AT and serotonin resulted in a more rapid secretion than either chemical alone.
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Affiliation(s)
- Maryam Masood
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada.
| | - Ian Orchard
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada.
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14
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Kromann SH, Hansson BS, Ignell R. Distribution of neuropeptides in the antennal lobes of male Spodoptera littoralis. Cell Tissue Res 2013; 354:431-40. [PMID: 23955643 DOI: 10.1007/s00441-013-1703-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Olfaction is an important sensory modality that regulates a plethora of behavioural expressions in insects. Processing of olfactory information takes place in the primary olfactory centres of the brain, namely the antennal lobes (ALs). Neuropeptides have been shown to be present in the olfactory system of various insect species. In the present study, we analyse the distribution of tachykinin, FMRFamide-related peptides, allatotropin, allatostatin, myoinhibitory peptides and SIFamide in the AL of the male Egyptian cotton leafworm, Spodoptera littoralis. Immunocytochemical analyses revealed that most neuropeptides were expressed in different subpopulations of AL neurons. Their arborisation patterns within the AL suggest a significant role of neuropeptide signalling in the modulation of AL processing. In addition to local interneurons, our analysis also revealed a diversity of extrinsic peptidergic neurons that connected the antennal lobe with other brain centres. Their distributions suggest that extrinsic neurons perform various types of context-related modulation.
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Affiliation(s)
- Sophie H Kromann
- Department of Plant Protection Biology, Unit of Chemical Ecology, Swedish University of Agricultural Sciences, Box 102, 230 53, Alnarp, Sweden,
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De Loof A, Boerjan B, Ernst UR, Schoofs L. The mode of action of juvenile hormone and ecdysone: towards an epi-endocrinological paradigm? Gen Comp Endocrinol 2013; 188:35-45. [PMID: 23454668 DOI: 10.1016/j.ygcen.2013.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 02/07/2013] [Accepted: 02/12/2013] [Indexed: 12/20/2022]
Abstract
In some insect species, two sites of juvenile hormone (JH) synthesis have been reported: the very well documented corpora allata that secrete JH for "general use", and the reproductive system, in particular the male accessory glands, in which the function of the sometimes huge amounts of JH (e.g. in Hyalophora cecropia) remains to be clarified. A recent finding in Schistocerca gregaria, namely that suppression of the ecdysteroid peak preceding a molt by RNAi of the Halloween genes spook, phantom and shade does not impede normal molting, challenges the (never experimentally proven) classical concept that such a peak is causally linked to a molt. Recent developments in epigenetic control of gene expression in both the honey bee and in locusts suggest that, in addition to the classical scheme of hormone-receptor (membrane- and/or nuclear) mode of action, there may be a third way. Upon combining these and other orphan data that do not fit in the commonly accepted textbook schemes, we here advance the working hypothesis that both JH and ecdysone might be important but overlooked players in epigenetic control of gene expression, in particular at extreme concentrations (peak values or total absence). In this review, we put forward how epi-endocrinology can complement classical arthropod endocrinology.
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Affiliation(s)
- Arnold De Loof
- Research Group of Functional Genomics and Proteomics, KU Leuven, Naamsestraat 59, Bus 2465, 3000 Leuven, Belgium.
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Hamanaka Y, Kinoshita M, Homberg U, Arikawa K. Immunocytochemical localization of amines and GABA in the optic lobe of the butterfly, Papilio xuthus. PLoS One 2012; 7:e41109. [PMID: 22844431 PMCID: PMC3402530 DOI: 10.1371/journal.pone.0041109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 06/21/2012] [Indexed: 11/19/2022] Open
Abstract
Butterflies have sophisticated color vision. While the spectral organization of the compound eye has been well characterized in the Japanese yellow swallowtail butterfly, Papilio xuthus, neural mechanisms underlying its color vision are largely unexplored. Towards a better understanding of signal processing in the visual system of P. xuthus, we used immunocytochemical techniques to analyze the distribution of transmitter candidates, namely, histamine, serotonin, tyramine and γ-aminobutyric acid (GABA). Photoreceptor terminals in the lamina and medulla exhibited histamine immunoreactivity as demonstrated in other insects. The anti-histamine antiserum also labeled a few large medulla neurons. Medulla intrinsic neurons and centrifugal neurons projecting to the lamina showed serotonin immunoreactivity. Tyramine immunostaining was detected in a subset of large monopolar cells (LMCs) in the lamina, transmedullary neurons projecting to the lobula plate, and cell bodies surrounding the first optic chiasma. An anti-GABA antiserum labeled a subset of LMCs and populations of columnar and tangential neurons surrounding the medulla. Each of the four antisera also labeled a few centrifugal neurons that innervate the lobula complex from the central brain, suggesting that they have neuromodulatory roles. A distinctive feature we found in this study is the possibility that tyramine and GABA act as transmitters in LMCs of P. xuthus, which has not been reported in any other insects so far.
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Affiliation(s)
- Yoshitaka Hamanaka
- Laboratory of Neuroethology, Sokendai, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, Japan
| | - Michiyo Kinoshita
- Laboratory of Neuroethology, Sokendai, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, Japan
| | - Uwe Homberg
- Department of Biology, Animal Physiology, University of Marburg, Marburg, Germany
| | - Kentaro Arikawa
- Laboratory of Neuroethology, Sokendai, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, Japan
- * E-mail:
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Heinrich R, Kunst M, Wirmer A. Reproduction-related sound production of grasshoppers regulated by internal state and actual sensory environment. Front Neurosci 2012; 6:89. [PMID: 22737107 PMCID: PMC3381836 DOI: 10.3389/fnins.2012.00089] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 05/29/2012] [Indexed: 12/04/2022] Open
Abstract
The interplay of neural and hormonal mechanisms activated by entero- and extero-receptors biases the selection of actions by decision making neuronal circuits. The reproductive behavior of acoustically communicating grasshoppers, which is regulated by short-term neural and longer-term hormonal mechanisms, has frequently been used to study the cellular and physiological processes that select particular actions from the species-specific repertoire of behaviors. Various grasshoppers communicate with species- and situation-specific songs in order to attract and court mating partners, to signal reproductive readiness, or to fend off competitors. Selection and coordination of type, intensity, and timing of sound signals is mediated by the central complex, a highly structured brain neuropil known to integrate multimodal pre-processed sensory information by a large number of chemical messengers. In addition, reproductive activity including sound production critically depends on maturation, previous mating experience, and oviposition cycles. In this regard, juvenile hormone released from the corpora allata has been identified as a decisive hormonal signal necessary to establish reproductive motivation in grasshopper females. Both regulatory systems, the central complex mediating short-term regulation and the corpora allata mediating longer-term regulation of reproduction-related sound production mutually influence each other’s activity in order to generate a coherent state of excitation that promotes or suppresses reproductive behavior in respective appropriate or inappropriate situations. This review summarizes our current knowledge about extrinsic and intrinsic factors that influence grasshopper reproductive motivation, their representation in the nervous system and their integrative processing that mediates the initiation or suppression of reproductive behaviors.
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Affiliation(s)
- Ralf Heinrich
- Department of Cellular Neurobiology, Institute for Zoology and Anthropology, University of Göttingen Göttingen, Germany
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Heuer CM, Kollmann M, Binzer M, Schachtner J. Neuropeptides in insect mushroom bodies. ARTHROPOD STRUCTURE & DEVELOPMENT 2012; 41:199-226. [PMID: 22401884 DOI: 10.1016/j.asd.2012.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/22/2012] [Accepted: 02/23/2012] [Indexed: 05/31/2023]
Abstract
Owing to their experimental amenability, insect nervous systems continue to be in the foreground of investigations into information processing in - ostensibly - simple neuronal networks. Among the cerebral neuropil regions that hold a particular fascination for neurobiologists are the paired mushroom bodies, which, despite their function in other behavioral contexts, are most renowned for their role in learning and memory. The quest to understand the processes that underlie these capacities has been furthered by research focusing on unraveling neuroanatomical connections of the mushroom bodies and identifying key players that characterize the molecular machinery of mushroom body neurons. However, on a cellular level, communication between intrinsic and extrinsic mushroom body neurons still remains elusive. The present account aims to provide an overview on the repertoire of neuropeptides expressed in and utilized by mushroom body neurons. Existing data for a number of insect representatives is compiled and some open gaps in the record are filled by presenting additional original data.
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Affiliation(s)
- Carsten M Heuer
- Philipps-University Marburg, Department of Biology, Animal Physiology, Marburg, Germany.
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Spit J, Badisco L, Verlinden H, Van Wielendaele P, Zels S, Dillen S, Vanden Broeck J. Peptidergic control of food intake and digestion in insects 1This review is part of a virtual symposium on recent advances in understanding a variety of complex regulatory processes in insect physiology and endocrinology, including development, metabolism, cold hardiness, food intake and digestion, and diuresis, through the use of omics technologies in the postgenomic era. CAN J ZOOL 2012. [DOI: 10.1139/z2012-014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Like all heterotrophic organisms, insects require a strict control of food intake and efficient digestion of food into nutrients to maintain homeostasis and to fulfill physiological tasks. Feeding and digestion are steered by both external and internal signals that are transduced by a multitude of regulatory factors, delivered either by neurons innervating the gut or mouthparts, or by midgut endocrine cells. The present review gives an overview of peptide regulators known to control feeding and digestion in insects. We describe the discovery and functional role in these processes for insect allatoregulatory peptides, diuretic hormones, FMRFamide-related peptides, (short) neuropeptide F, proctolin, saliva production stimulating peptides, kinins, and tachykinins. These peptides control either gut myoactivity, food intake, and (or) release of digestive enzymes. Some peptides exert their action at multiple levels, possibly having a biological function that depends on their site of delivery. Many regulatory peptides have been physically extracted from different insect species. However, multiple peptidomics, proteomics, transcriptomics, and genome sequencing projects have led to increased discovery and prediction of peptide (precursor) and receptor sequences. In combination with physiological experiments, these large-scale projects have already led to important steps forward in unraveling the physiology of feeding and digestion in insects.
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Affiliation(s)
- J. Spit
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - L. Badisco
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - H. Verlinden
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - P. Van Wielendaele
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - S. Zels
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - S. Dillen
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
| | - J. Vanden Broeck
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
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Schulze J, Neupert S, Schmidt L, Predel R, Lamkemeyer T, Homberg U, Stengl M. Myoinhibitory peptides in the brain of the cockroach Leucophaea maderae and colocalization with pigment-dispersing factor in circadian pacemaker cells. J Comp Neurol 2012; 520:1078-97. [DOI: 10.1002/cne.22785] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Neupert S, Fusca D, Schachtner J, Kloppenburg P, Predel R. Toward a single-cell-based analysis of neuropeptide expression in Periplaneta americana antennal lobe neurons. J Comp Neurol 2012; 520:694-716. [DOI: 10.1002/cne.22745] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Myoinhibitory peptide (MIP) immunoreactivity in the visual system of the blowfly Calliphora vomitoria in relation to putative clock neurons and serotonergic neurons. Cell Tissue Res 2011; 345:125-35. [PMID: 21660541 DOI: 10.1007/s00441-011-1198-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
A few types of peptidergic clock neurons have been identified in the fruitfly Drosophila, whereas in blowflies, only pigment-dispersing factor (PDF)-immunoreactive lateral ventral clock neurons (LN(v)s) have been described. In blowflies, but not Drosophila, a subset of these PDF-expressing neurons supplies axon branches to a region outside the synaptic layer of the lamina, the most peripheral optic lobe neuropil. In Drosophila, similar lamina processes are instead supplied by non-clock neurons (LMIo) that express myoinhibitory peptide (MIP). We have investigated the distribution of MIP-immunoreactive neurons in the visual system of the blowfly Calliphora vomitoria and found neurons resembling the three LMIos, but without processes to the lamina. In Calliphora, PDF-immunoreactive processes of LN(v)s in the lamina closely impinge on branching serotonin-immunoreactive axon terminations in the same region. We have also identified, in the blowfly, two types of putative clock neurons that label with an antiserum to ion-transport peptide (ITP). The presence of serotonin-immunoreactive neurons supplying processes to the lamina seems to be a conserved feature in dipteran flies. The morphology of the two types of ITP-immunoreactive clock neurons might also be conserved. However, peptidergic neurons with branches converging on the serotonin-immunoreactive neurons in the lamina are of different morphological types and express PDF in blowflies and MIP in Drosophila. The central circuitry of these PDF- and MIP-expressing neurons probably differs; consequently, whether their convergence on serotonergic neurons subserves similar functions in the two species is unclear.
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Chronic fetal hypoxia produces selective brain injury associated with altered nitric oxide synthases. Am J Obstet Gynecol 2011; 204:254.e16-28. [PMID: 21272843 DOI: 10.1016/j.ajog.2010.11.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/18/2010] [Accepted: 11/09/2010] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the impact of chronic hypoxia on the nitric oxide synthase isoenzymes in specific brain structures. STUDY DESIGN Time-mated pregnant guinea pigs were exposed to 10.5% molecular oxygen for 14 days (animals with chronic fetal hypoxia; HPX) or room air (control animals; NMX); L-N6-(1-iminoethyl)-lysine (L-NIL; an inducible nitric oxide synthase inhibitor, 1 mg/kg/d) was administered to HPX group for 14 days (L-NIL + HPX). Fetal brains were harvested at term. Multilabeled immunofluorescence was used to generate a brain injury map. Laser capture microdissection and quantitative polymerase chain reaction were applied; cell injury markers, apoptosis activation, neuron loss, total nitric oxide, and the levels of individual nitric oxide synthase isoenzymes were quantified. RESULTS Chronic hypoxia causes selective fetal brain injury rather than global. Injury is associated with differentially affected nitric oxide synthases in both neurons and glial cells, with inducible macrophage-type nitric oxide synthase up-regulated at all injury sites. L-NIL attenuated the injury, despite continued hypoxia. CONCLUSION These studies demonstrate that chronic hypoxia selectively injures the fetal brain in part by the differential regulation of nitric oxide synthase isoenzymes in an anatomic- and cell-specific manner.
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Wirmer A, Heinrich R. Nitric oxide/cGMP signaling in the corpora allata of female grasshoppers. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:94-107. [PMID: 20932971 DOI: 10.1016/j.jinsphys.2010.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 09/27/2010] [Accepted: 09/29/2010] [Indexed: 05/30/2023]
Abstract
The corpora allata (CA) of various insects express enzymes with fixation resistant NADPHdiaphorase activity. In female grasshoppers, juvenile hormone (JH) released from the CA is necessary to establish reproductive readiness, including sound production. Previous studies demonstrated that female sound production is also promoted by systemic inhibition of nitric oxide (NO) formation. In addition, allatotropin and allatostatin expressing central brain neurons were located in close vicinity of NO generating cells. It was therefore speculated that NO signaling may contribute to the control of juvenile hormone release from the CA. This study demonstrates the presence of NO/cGMP signaling in the CA of female Chorthippus biguttulus. CA parenchymal cells exhibit NADPHdiaphorase activity, express anti NOS immunoreactivity and accumulate citrulline, which is generated as a byproduct of NO generation. Varicose terminals from brain neurons in the dorsal pars intercerebralis and pars lateralis that accumulate cGMP upon stimulation with NO donors serve as intrinsic targets of NO in the CA. Both accumulation of citrulline and cyclic GMP were inhibited by the NOS inhibitor aminoguanidine, suggesting that NO in CA is produced by NOS. These results suggest that NO is a retrograde transmitter that provides feedback to projection neurons controlling JH production. Combined immunostainings and backfill experiments detected CA cells with processes extending into the CC and the protocerebrum that expressed immunoreactivity against the pan-neural marker anti-HRP. Allatostatin and allatotropin immunopositive brain neurons do not express NOS but subpopulations accumulate cGMP upon NO-formation. Direct innervation of CA by these peptidergic neurons was not observed.
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Affiliation(s)
- Andrea Wirmer
- Institute for Zoology, University of Göttingen, 37073 Göttingen, Germany
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Kahsai L, Winther ÅM. Chemical neuroanatomy of the Drosophila central complex: Distribution of multiple neuropeptides in relation to neurotransmitters. J Comp Neurol 2010; 519:290-315. [DOI: 10.1002/cne.22520] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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El Jundi B, Homberg U. Evidence for the possible existence of a second polarization-vision pathway in the locust brain. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:971-979. [PMID: 20488187 DOI: 10.1016/j.jinsphys.2010.05.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 05/11/2010] [Accepted: 05/11/2010] [Indexed: 05/29/2023]
Abstract
For spatial orientation and navigation, many insects derive compass information from the polarization pattern of the blue sky. The desert locust Schistocerca gregaria detects polarized light with a specialized dorsal rim area of its compound eye. In the locust brain, polarized-light signals are passed through the anterior optic tract and tubercle to the central complex which most likely serves as an internal sky compass. Here, we suggest that neurons of a second visual pathway, via the accessory medulla and posterior optic tubercle, also provide polarization information to the central complex. Intracellular recordings show that two types of neuron in this posterior pathway are sensitive to polarized light. One cell type connects the dorsal rim area of the medulla with the medulla and accessory medulla, and a second type connects the bilaterally paired posterior optic tubercles. Given the evidence for a role of the accessory medulla as the master clock controlling circadian changes in behavioral activity in flies and cockroaches, our data open the possibility that time-compensated polarized-light signals may reach the central complex via this pathway for time-compensated sky-compass navigation.
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Affiliation(s)
- Basil El Jundi
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032 Marburg, Germany
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Wei H, el Jundi B, Homberg U, Stengl M. Implementation of pigment-dispersing factor-immunoreactive neurons in a standardized atlas of the brain of the cockroach Leucophaea maderae. J Comp Neurol 2010; 518:4113-33. [DOI: 10.1002/cne.22471] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Clynen E, Schoofs L. Peptidomic survey of the locust neuroendocrine system. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:491-507. [PMID: 19524670 DOI: 10.1016/j.ibmb.2009.06.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 06/02/2009] [Accepted: 06/04/2009] [Indexed: 05/27/2023]
Abstract
Neuropeptides are important controlling agents in animal physiology. In order to understand their role and the ways in which neuropeptides behave and interact with one another, information on their time and sites of expression is required. We here used a combination of MALDI-TOF and ESI-Q-TOF mass spectrometry to make an inventory of the peptidome of different parts (ganglia and nerves) of the central nervous system from the desert locust Schistocerca gregaria and the African migratory locust Locusta migratoria. This way, we analysed the brain, suboesophageal ganglion, retrocerebral complex, stomatogastric nervous system, thoracic ganglia, abdominal ganglia and abdominal neurohemal organs. The result is an overview of the distribution of sixteen neuropeptide families, i.e. pyrokinins, pyrokinin-like peptides, periviscerokinins, tachykinins, allatotropin, accessory gland myotropin, FLRFamide, (short) neuropeptide F, allatostatins, insulin-related peptide co-peptide, ion-transport peptide co-peptide, corazonin, sulfakinin, orcokinin, hypertrehalosaemic hormone and adipokinetic hormones (joining peptides) throughout the locust neuroendocrine system.
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Affiliation(s)
- Elke Clynen
- Research Group Functional Genomics and Proteomics, K.U. Leuven, Naamsestraat 59, 3000 Leuven, Belgium
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Verlinden H, Badisco L, Marchal E, Van Wielendaele P, Vanden Broeck J. Endocrinology of reproduction and phase transition in locusts. Gen Comp Endocrinol 2009; 162:79-92. [PMID: 19084019 DOI: 10.1016/j.ygcen.2008.11.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 10/10/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
Abstract
In the last decade, important progress has been made in the experimental analysis of the endocrine mechanisms controlling reproduction and phase transition in locusts. Phase transition is a very fascinating, but complex, phenomenon of phenotypic plasticity that is triggered by changes in population density and can lead to the formation of extremely devastating hopper bands and adult gregarious locust swarms. While some phase characteristics change within hours, others appear more gradually in the next stage(s), or even in the next generation(s). In adults, the phase status also has a major influence on the process of reproduction. A better understanding of how solitarious locusts become gregarious and how this switch affects reproductive physiology may result in novel strategies to fight locust plagues. In this paper, we will review the current knowledge concerning this close interaction between locust phase polyphenism and reproduction.
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Affiliation(s)
- Heleen Verlinden
- Animal Physiology and Neurobiology, K.U.Leuven, Naamsestraat 59, 3000 Leuven, Vlaams-Brabant, Belgium
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Neupert S, Schattschneider S, Predel R. Allatotropin-related peptide in cockroaches: identification via mass spectrometric analysis of single identified neurons. Peptides 2009; 30:489-94. [PMID: 19071174 DOI: 10.1016/j.peptides.2008.10.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/30/2008] [Accepted: 10/30/2008] [Indexed: 11/23/2022]
Abstract
The first insect allatotropin-related peptide (ATRP) was isolated from head extracts of the adult sphinx moth Manduca sexta [Kataoka H, Toschi A, Li JP, Carney RL, Schooley DA, Kramer SJ. Identification of an allatotropin from adult Manduca sexta. Science 1989;243:1481-3.]. Meanwhile ATRPs are known from different holometabolous insects but only a single ATRP could be identified from hemimetabolous insects [Paemen L, Tips A, Schoofs L, Proost P, Van Damme J, De Loof A. Lom-AG-myotropin: a novel myotropic peptide from the male accessory glands of Locusta migratoria. Peptides 1991;12:7-10.]. This means that the extensive analysis of neuropeptides from Leucophaea maderae and Periplaneta americana, which led to the discovery of many novel insect neuropeptides, did not result in the detection of any ATRP. In this study, we used another approach to find a cockroach ATRP by first identifying Manse-AT immunoreactive neurons in the terminal ganglion that can be stained by retrograde labeling and are suitable for dissection and subsequent mass spectrometric analysis. The peptidomic analysis of these putative ATRP neurons paved the way for the identification of the first cockroach ATRP. MALDI-TOF/TOF tandem mass spectrometry revealed a sequence identity with Locmi-AG-MT-1 which classifies this ATRP as a highly conserved neuropeptide. A mass spectrometric screening of the nervous system allowed the detection of ATRP-ion signals in different parts of the CNS of P. americana as well as L. maderae. The data obtained in this study will be incorporated in a map of peptidergic neurons from the CNS of the American cockroach, P. americana.
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Affiliation(s)
- Susanne Neupert
- Institute of General Zoology and Animal Physiology, Friedrich-Schiller-University Jena, Erbertstrasse 1, 07743 Jena, Germany.
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Neupert S, Russell WK, Russell DH, López JD, Predel R, Nachman RJ. Neuropeptides in Heteroptera: identification of allatotropin-related peptide and tachykinin-related peptides using MALDI-TOF mass spectrometry. Peptides 2009; 30:483-8. [PMID: 19084564 DOI: 10.1016/j.peptides.2008.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 11/05/2008] [Accepted: 11/06/2008] [Indexed: 11/18/2022]
Abstract
Recently, the peptidomic analysis of neuropeptides from the retrocerebral complex and abdominal perisympathetic organs of polyphagous stinkbugs (Pentatomidae) revealed the group-specific sequences of pyrokinins, CAPA peptides (CAPA-periviscerokinins/PVKs and CAPA-pyrokinin), myosuppressin, corazonin, adipokinetic hormone, and short neuropeptide F. In this study, we used mass spectrometric profiling of nervous tissue from the species-rich taxon Hemiptera to identify products of two previously unobserved neuropeptide genes from these species, namely allatotropin-related peptide (ATRP) and tachykinin-related peptides (TKRPs). Since neither TKRPs nor allatotropin are accumulated in neurohemal organs, immunocytochemical data were analyzed to find potential accumulation sites within the central nervous system. By mass spectrometry, TKRPs were found to be accumulated in the antennal lobes, and ATRP was identified in the most posterior region of the abdominal ventral nerve cord and fourth abdominal nerves. In addition to neuropeptides from stink bugs, TKRPs and ATRP were also identified from the distantly related bugs Oncopeltus fasciatus (Lygaeidae) and Pyrrhocoris apterus (Pyrrhocoridae). In total, six TKRPs and one ATRP from each species could be elucidated by tandem mass spectrometry. The ATRP of all species is sequence-identical with Locusta migratoria accessory gland myotropin-1 (Lom-AG-MT-1), a member of the highly conserved insect allatotropin family.
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Affiliation(s)
- Susanne Neupert
- Areawide Pest Management Research, Southern Plains Agricultural Research Center, USDA, 2881 F&B Road, College Station, TX 77845, USA.
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Farris SM. Tritocerebral tract input to the insect mushroom bodies. ARTHROPOD STRUCTURE & DEVELOPMENT 2008; 37:492-503. [PMID: 18590832 DOI: 10.1016/j.asd.2008.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 05/20/2008] [Accepted: 05/21/2008] [Indexed: 05/26/2023]
Abstract
Insect mushroom bodies, best known for their role in olfactory processing, also receive sensory input from other modalities. In crickets and grasshoppers, a tritocerebral tract containing afferents from palp mechanosensory and gustatory centers innervates the accessory calyx. The accessory calyx is uniquely composed of Class III Kenyon cells, and was shown by immunohistochemistry to be present sporadically across several insect orders. Neuronal tracers applied to the source of tritocerebral tract axons in several species of insects demonstrated that tritocerebral tract innervation of the mushroom bodies targeted the accessory calyx when present, the primary calyces when an accessory calyx was not present, or both. These results suggest that tritocerebral tract input to the mushroom bodies is likely ubiquitous, reflecting the importance of gustation for insect behavior. The scattered phylogenetic distribution of Class III Kenyon cells is also proposed to represent an example of generative homology, in which the developmental program for forming a structure is retained in all members of a lineage, but the program is not "run" in all branches.
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Affiliation(s)
- Sarah M Farris
- Department of Biology, West Virginia University, 3139 Life Sciences Building, 53 Campus Drive, Morgantown, WV 26506, USA.
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Sinakevitch I, Sjöholm M, Hansson BS, Strausfeld NJ. Global and local modulatory supply to the mushroom bodies of the moth Spodoptera littoralis. ARTHROPOD STRUCTURE & DEVELOPMENT 2008; 37:260-272. [PMID: 18406668 PMCID: PMC4876857 DOI: 10.1016/j.asd.2008.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 01/05/2008] [Accepted: 01/08/2008] [Indexed: 05/26/2023]
Abstract
The moth Spodoptera littoralis, is a major pest of agriculture whose olfactory system is tuned to odorants emitted by host plants and conspecifics. As in other insects, the paired mushroom bodies are thought to play pivotal roles in behaviors that are elicited by contextual and multisensory signals, amongst which those of specific odors dominate. Compared with species that have elaborate behavioral repertoires, such as the honey bee Apis mellifera or the cockroach Periplaneta americana, the mushroom bodies of S. littoralis were originally viewed as having a simple cellular organization. This has been since challenged by observations of putative transmitters and neuromodulators. As revealed by immunocytology, the spodopteran mushroom bodies, like those of other taxa, are subdivided longitudinally into discrete neuropil domains. Such divisions are further supported by the present study, which also demonstrates discrete affinities to different mushroom body neuropils by antibodies raised against two putative transmitters, glutamate and gamma-aminobutyric acid, and against three putative neuromodulatory substances: serotonin, A-type allatostatin, and tachykinin-related peptides. The results suggest that in addition to longitudinal divisions of the lobes, circuits in the calyces and lobes are likely to be independently modulated.
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Affiliation(s)
- Irina Sinakevitch
- IBDML-UMR 6216, Case 907 Parc Scientifique de Luminy, 13288 Marseille, Cedex 9, France
| | - Marcus Sjöholm
- Department of Crop Science, Swedish University of Agricultural Sciences, SE-23053, Alnarp, Sweden
| | - Bill S. Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knoell-Strasse 8, D-07745 Jena, Germany
| | - Nicholas J. Strausfeld
- Arizona Research Laboratories Division of Neurobiology and Center for Insect Science, University of Arizona, Tucson, AZ, 85721, USA
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Utz S, Huetteroth W, Vömel M, Schachtner J. Mas-allatotropin in the developing antennal lobe of the sphinx mothManduca sexta: Distribution, time course, developmental regulation, and colocalization with other neuropeptides. Dev Neurobiol 2008; 68:123-42. [DOI: 10.1002/dneu.20579] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rø H, Müller D, Mustaparta H. Anatomical organization of antennal lobe projection neurons in the moth Heliothis virescens. J Comp Neurol 2007; 500:658-75. [PMID: 17154270 DOI: 10.1002/cne.21194] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A prerequisite for understanding how odor information is coded in the central nervous system is to know the morphology and spatial relationship of the principal neurons forming the olfactory pathways. The present account provides an anatomical description of the morphology of the neuronal connections between the antennal lobe and the protocerebrum in the moth Heliothis virescens, a species used for studies of olfactory processing and learning. Intracellular labeling and antennal lobe focal injections with dextran fluorescent markers were combined with neuropil immunostaining and three-dimensional reconstructions. The experiments revealed four antennocerebral tracts, the inner, middle, outer, and dorsomedial, and eight morphological types of projection neurons in addition to a neuron with an unpaired median soma in the subesophageal ganglion. Multiglomerular projection neurons, present in all but the dorsomedial antennocerebral tract, project in several olfactory foci of the protocerebral neuropil. With few exceptions, these neurons do not innervate the calyces of the mushroom body. Uniglomerular projection neurons appear most numerous in the inner antennocerebral tract but are also present in the outer and dorsomedial tracts. These neurons always ramify in the calyces of the mushroom body and in the lateral horn. The projection areas of the neurons following different tracts are largely separated in the secondary olfactory centers. This is most evident in the lateral horn, whereas, in the calyces, the axonal ramifications are more intermingled. The mushroom body architecture, revealed by neuropil immunolabeling, showed striking similarities to that of other lepidopteran species as well as insects of other taxa.
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Affiliation(s)
- Helge Rø
- Neuroscience Unit, Department of Biology, Norwegian University of Science and Technology, N-7489 Trondheim, Norway
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Nässel DR, Homberg U. Neuropeptides in interneurons of the insect brain. Cell Tissue Res 2006; 326:1-24. [PMID: 16761145 DOI: 10.1007/s00441-006-0210-8] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Accepted: 03/28/2006] [Indexed: 10/24/2022]
Abstract
A large number of neuropeptides has been identified in the brain of insects. At least 35 neuropeptide precursor genes have been characterized in Drosophila melanogaster, some of which encode multiple peptides. Additional neuropeptides have been found in other insect species. With a few notable exceptions, most of the neuropeptides have been demonstrated in brain interneurons of various types. The products of each neuropeptide precursor seem to be co-expressed, and each precursor displays a unique neuronal distribution pattern. Commonly, each type of neuropeptide is localized to a relatively small number of neurons. We describe the distribution of neuropeptides in brain interneurons of a few well-studied insect species. Emphasis has been placed upon interneurons innervating specific brain areas, such as the optic lobes, accessory medulla, antennal lobes, central body, and mushroom bodies. The functional roles of some neuropeptides and their receptors have been investigated in D. melanogaster by molecular genetics techniques. In addition, behavioral and electrophysiological assays have addressed neuropeptide functions in the cockroach Leucophaea maderae. Thus, the involvement of brain neuropeptides in circadian clock function, olfactory processing, various aspects of feeding behavior, and learning and memory are highlighted in this review. Studies so far indicate that neuropeptides can play a multitude of functional roles in the brain and that even single neuropeptides are likely to be multifunctional.
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Affiliation(s)
- Dick R Nässel
- Department of Zoology, Stockholm University, Sweden.
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Berg BG, Schachtner J, Utz S, Homberg U. Distribution of neuropeptides in the primary olfactory center of the heliothine moth Heliothis virescens. Cell Tissue Res 2006; 327:385-98. [PMID: 17013588 DOI: 10.1007/s00441-006-0318-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Accepted: 08/02/2006] [Indexed: 11/28/2022]
Abstract
Neuropeptides are a diverse widespread class of signaling substances in the nervous system. As a basis for the analysis of peptidergic neurotransmission in the insect olfactory system, we have studied the distribution of neuropeptides in the antennal lobe of the moth Heliothis virescens. Immunocytochemical experiments with antisera recognizing A-type allatostatins (AST-As), Manduca sexta allatotropin (Mas-AT), FMRFamide-related peptides (FaRPs), and tachykinin-related peptides (TKRPs) have shown that members of all four peptide families are present in local interneurons of the antennal lobe. Whereas antisera against AST-As, Mas-AT, and FaRPs give similar staining patterns characterized by dense meshworks of processes confined to the core of all antennal-lobe glomeruli, TKRPs are present only in neurons with blebby processes distributed throughout each glomerulus. In addition to local neurons, a pair of centrifugal neurons with cell bodies in the lateral subesophageal ganglion, arborizations in the antennal lobe, and projections in the inner antenno-cerebral tracts exhibits tachykinin immunostaining. Double-label immunofluorescence has detected the co-localization of AST-As, Mas-AT, and FaRPs in certain local interneurons, whereas TKRPs occurs in a distinct population. MALDI-TOF mass spectrometry has revealed nearly 50 mass peaks in the antennal lobe. Seven of these masses (four AST-As, two N-terminally extended FLRFamides, and Mas-AT) match known moth neuropeptides. The data thus show that local interneurons of the moth antennal lobe are highly differentiated with respect to their neuropeptide content. The antennal lobe therefore represents an ideal preparation for the future analysis of peptide signaling in insect brain.
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Affiliation(s)
- Bente G Berg
- Neuroscience Unit, Department of Psychology, Norwegian University of Science and Technology, 7489, Trondheim, Norway.
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Sjöholm M, Sinakevitch I, Strausfeld NJ, Ignell R, Hansson BS. Functional division of intrinsic neurons in the mushroom bodies of male Spodoptera littoralis revealed by antibodies against aspartate, taurine, FMRF-amide, Mas-allatotropin and DC0. ARTHROPOD STRUCTURE & DEVELOPMENT 2006; 35:153-168. [PMID: 18089067 DOI: 10.1016/j.asd.2006.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 03/20/2006] [Accepted: 05/10/2006] [Indexed: 05/25/2023]
Abstract
The aim of this study was to further reveal the organization of Kenyon cells in the mushroom body calyx and lobes of the male moth Spodoptera littoralis, by using immunocytochemical labeling. Subdivisions of the mushroom bodies were identified employing antisera raised against the amino acids taurine and aspartate, the neuropeptides FMRF-amide and Mas-allatotropin, and against the protein kinase A catalytic subunit DC0. These antisera have previously been shown to label subsets of Kenyon cells in other species. The present results show that the organization of the mushroom body lobes into discrete divisions, described from standard neuroanatomical methods, is confirmed by immunocytology and shown to be further elaborated. Anti-taurine labels the accessory Y-tract, the gamma division of the lobes, and a thin subdivision of the most posterior component of the lobes. Aspartate antiserum labels the entire mushroom body. FMRF-amide-like immunolabeling is pronounced in the gamma division and in the anterior perimeter of the alpha/beta and alpha'/beta' divisions. Mas-allatotropin-like immunolabeling shows the opposite of FMRF-amide-like and taurine-like immunolabeling: the gamma division and the accessory Y-system is immunonegative whereas strong labeling is seen in both the alpha/beta and alpha'/beta' divisions. The present results agree with findings from other insects that mushroom bodies are anatomically divided into discrete parallel units. Functional and developmental implications of this organization are discussed.
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Affiliation(s)
- Marcus Sjöholm
- Department of Crop Science, Swedish University of Agricultural Sciences, SE-23053, Alnarp, Sweden
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Rankin SM, Kwok R, Seymour ML, Shaon Rahman U, Tobe SS. Effects of Manduca allatotropin and localization of Manduca allatotropin-immunoreactive cells in earwigs. Comp Biochem Physiol B Biochem Mol Biol 2005; 142:113-22. [PMID: 16019245 DOI: 10.1016/j.cbpc.2005.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 06/14/2005] [Accepted: 06/17/2005] [Indexed: 11/23/2022]
Abstract
Manduca sexta allatotropin (Manse-AT) was first isolated on the basis of its ability to stimulate production of juvenile hormone in that insect. We examined whether this neuropeptide affects corpus allatum activity and visceral muscle contraction in adult females of the earwig, Euborellia annulipes. We also assessed the presence of allatotropin-like material in tissues using immunocytochemistry. Manse-AT at 1 nM to 10 muM stimulated juvenile hormone production in vitro by glands of low activity from 2-day virgin females. In glands of high activity from 12-day mated females, 1 and 100 nM allatotropin were effective, but 10 muM was not. Similarly, hindguts of 2-day and 12-day females significantly increased in motility in vitro in response to Manse-AT. A monoclonal antibody to Manse-AT was used to demonstrate allatotropin-like material throughout the nervous system of 2-day, virgin females. Immunoreactivity was most pronounced within varicosities of the corpora cardiaca and perisympathetic organs. No immunofluorescence was observed in gut tissue. Lastly, we showed that extract of retrocerebral complexes also enhanced in vitro hindgut motility from 2-day virgin females, in a dose-dependent manner. These results indicate material similar to M. sexta allatotropin in female earwigs and that such peptides may modulate juvenile hormone biosynthesis and visceral muscle contractions. Sensitivity to the peptides may change with physiological stage.
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Affiliation(s)
- Susan M Rankin
- Department of Biology, Allegheny College, Meadville, PA 16335, USA.
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Kurylas AE, Ott SR, Schachtner J, Elphick MR, Williams L, Homberg U. Localization of nitric oxide synthase in the central complex and surrounding midbrain neuropils of the locust Schistocerca gregaria. J Comp Neurol 2005; 484:206-23. [PMID: 15736229 DOI: 10.1002/cne.20467] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitric oxide (NO), generated enzymatically by NO synthase (NOS), acts as an important signaling molecule in the nervous systems of vertebrates and invertebrates. In insects, NO has been implicated in development and in various aspects of sensory processing. To understand better the contribution of NO signaling to higher level brain functions, we analyzed the distribution of NOS in the midbrain of a model insect species, the locust Schistocerca gregaria, by using NADPH diaphorase (NADPHd) histochemistry after methanol/formalin fixation; results were validated by NOS immunohistochemistry. NADPHd yielded much higher sensitivity and resolution, but otherwise the two techniques resulted in corresponding labeling patterns throughout the brain, except for intense immunostaining but only weak NADPHd staining in median neurosecretory cells. About 470 neuronal cell bodies in the locust midbrain were NADPHd-positive positive, and nearly all major neuropil centers contained dense, sharply stained arborizations. We report several novel types of NOS-expressing neurons, including small ocellar interneurons and antennal sensory neurons that bypass the antennal lobe. Highly prominent labeling occurred in the central complex, a brain area involved in sky-compass orientation, and was analyzed in detail. Innervation by NOS-expressing fibers was most notable in the central body upper and lower divisions, the lateral accessory lobes, and the noduli. About 170 NADPHd-positive neurons contributed to this innervation, including five classes of tangential neuron, two systems of pontine neuron, and a system of columnar neurons. The results provide new insights into the neurochemical architecture of the central complex and suggest a prominent role for NO signaling in this brain area.
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Affiliation(s)
- Angela E Kurylas
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität, D-35032 Marburg, Germany
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