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Sasao M, Uno T, Kitagawa R, Matsui A, Toryu F, Mizoguchi A, Kanamaru K, Sakamoto K, Uno Y. Localization of SNARE proteins in the brain and corpus allatum of Bombyx mori. Histochem Cell Biol 2023; 159:199-208. [PMID: 36129568 DOI: 10.1007/s00418-022-02153-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2022] [Indexed: 11/04/2022]
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) make up the core machinery that mediates membrane fusion. SNAREs, syntaxin, synaptosome-associated protein (SNAP), and synaptobrevin form a tight SNARE complex that brings the vesicle and plasma membranes together and is essential for membrane fusion. The cDNAs of SNAP-25, VAMP2, and Syntaxin 1A from Bombyx mori were inserted into a plasmid, transformed into Escherichia coli, and purified. We then produced antibodies against the SNAP-25, VAMP2, and Syntaxin 1A of Bombyx mori of rabbits and rats, which were used for immunohistochemistry. Immunohistochemistry results revealed that the expression of VAMP2 was restricted to neurons in the pars intercerebralis (PI), dorsolateral protocerebrum (DL), and central complex (CX) of the brain. SNAP-25 was restricted to neurons in the PI and the CX of the brain. Syntaxin 1A was restricted to neurons in the PI and DL of the brain. VAMP2 co-localized with SNAP-25 in the CX, and with Syntaxin 1A in the PI and DL. VAMP2, SNAP-25, and Syntaxin 1A are present in the CA. Bombyxin-immunohistochemical reactivities (IRs) of brain and CA overlapped with VAMP2-, SNAP-25, and Syntaxin 1A-IRs. VAMP2 and Syntaxin 1A are present in the prothoracicotropic hormone (PTTH)-secretory neurons of the brain.
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Affiliation(s)
- Mako Sasao
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Tomohide Uno
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
| | - Risa Kitagawa
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Asuka Matsui
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Fumika Toryu
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Akira Mizoguchi
- Division of Liberal Arts and Sciences, Aichi Gakuin University, Nisshin, Aichi, 470-0195, Japan
| | - Kengo Kanamaru
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Katsuhiko Sakamoto
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Yuichi Uno
- Department of Plant Resource Science, Faculty of Agriculture, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan
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Kymre JH, Chu X, Ian E, Berg BG. Organization of the parallel antennal-lobe tracts in the moth. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:707-721. [PMID: 36112200 PMCID: PMC9734247 DOI: 10.1007/s00359-022-01566-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/16/2022] [Accepted: 08/25/2022] [Indexed: 12/14/2022]
Abstract
The olfactory pathways of the insect brain have been studied comprehensively for more than 40 years, yet the last decade has included a particularly large accumulation of new information relating to this system's structure. In moths, sharp intracellular recording and staining has been used to elucidate the anatomy and physiology of output neurons from the primary olfactory center, the antennal lobe. This review concentrates on the connection patterns characterizing these projection neurons, which follow six separate antennal-lobe tracts. In addition to highlighting the connections between functionally distinct glomerular clusters and higher-order olfactory neuropils, we discuss how parallel tracts in the male convey distinct features of the social signals released by conspecific and heterospecific females. Finally, we consider the current state of knowledge regarding olfactory processing in the moth's protocerebrum and make suggestions as to how the information concerning antennal-lobe output may be used to design future studies.
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Affiliation(s)
- Jonas Hansen Kymre
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Xi Chu
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Elena Ian
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente Gunnveig Berg
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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A Review of Effects of Environment on Brain Size in Insects. INSECTS 2021; 12:insects12050461. [PMID: 34067515 PMCID: PMC8156428 DOI: 10.3390/insects12050461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary What makes a big brain is fascinating since it is considered as a measure of intelligence. Above all, brain size is associated with body size. If species that have evolved with complex social behaviours possess relatively bigger brains than those deprived of such behaviours, this does not constitute the only factor affecting brain size. Other factors such as individual experience or surrounding environment also play roles in the size of the brain. In this review, I summarize the recent findings about the effects of environment on brain size in insects. I also discuss evidence about how the environment has an impact on sensory systems and influences brain size. Abstract Brain size fascinates society as well as researchers since it is a measure often associated with intelligence and was used to define species with high “intellectual capabilities”. In general, brain size is correlated with body size. However, there are disparities in terms of relative brain size between species that may be explained by several factors such as the complexity of social behaviour, the ‘social brain hypothesis’, or learning and memory capabilities. These disparities are used to classify species according to an ‘encephalization quotient’. However, environment also has an important role on the development and evolution of brain size. In this review, I summarise the recent studies looking at the effects of environment on brain size in insects, and introduce the idea that the role of environment might be mediated through the relationship between olfaction and vision. I also discussed this idea with studies that contradict this way of thinking.
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Paffhausen BH, Fuchs I, Duer A, Hillmer I, Dimitriou IM, Menzel R. Neural Correlates of Social Behavior in Mushroom Body Extrinsic Neurons of the Honeybee Apis mellifera. Front Behav Neurosci 2020; 14:62. [PMID: 32372927 PMCID: PMC7186758 DOI: 10.3389/fnbeh.2020.00062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/30/2020] [Indexed: 11/13/2022] Open
Abstract
The social behavior of honeybees (Apis mellifera) has been extensively investigated, but little is known about its neuronal correlates. We developed a method that allowed us to record extracellularly from mushroom body extrinsic neurons (MB ENs) in a freely moving bee within a small but functioning mini colony of approximately 1,000 bees. This study aimed to correlate the neuronal activity of multimodal high-order MB ENs with social behavior in a close to natural setting. The behavior of all bees in the colony was video recorded. The behavior of the recorded animal was compared with other hive mates and no significant differences were found. Changes in the spike rate appeared before, during or after social interactions. The time window of the strongest effect on spike rate changes ranged from 1 s to 2 s before and after the interaction, depending on the individual animal and recorded neuron. The highest spike rates occurred when the experimental animal was situated close to a hive mate. The variance of the spike rates was analyzed as a proxy for high order multi-unit processing. Comparing randomly selected time windows with those in which the recorded animal performed social interactions showed a significantly increased spike rate variance during social interactions. The experimental set-up employed for this study offers a powerful opportunity to correlate neuronal activity with intrinsically motivated behavior of socially interacting animals. We conclude that the recorded MB ENs are potentially involved in initiating and controlling social interactions in honeybees.
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Affiliation(s)
| | | | | | | | | | - Randolf Menzel
- Neurobiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany
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Hamanaka Y, Mizunami M. Tyrosine hydroxylase-immunoreactive neurons in the mushroom body of the field cricket, Gryllus bimaculatus. Cell Tissue Res 2018; 376:97-111. [PMID: 30578444 DOI: 10.1007/s00441-018-2969-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 11/19/2018] [Indexed: 12/20/2022]
Abstract
The mushroom body of the insect brain participates in processing and integrating multimodal sensory information and in various forms of learning. In the field cricket, Gryllus bimaculatus, dopamine plays a crucial role in aversive memory formation. However, the morphologies of dopamine neurons projecting to the mushroom body and their potential target neurons, the Kenyon cells, have not been characterized. Golgi impregnations revealed two classes of Kenyon cells (types I and II) and five different types of extrinsic fibers in the mushroom body. Type I cells, which are further divided into two subtypes (types I core and I surface), extend their dendrites into the anterior calyx, whereas type II cells extend many bushy dendritic branches into the posterior calyx. Axons of the two classes bifurcate between the pedunculus and lobes to form the vertical, medial and γ lobes. Immunocytochemistry to tyrosine hydroxylase (TH), a rate-limiting enzyme in dopamine biosynthesis, revealed the following four distinct classes of neurons: (1) TH-SLP projecting to the distal vertical lobe; (2) TH-IP1 extending to the medial and γ lobes; (3) TH-IP2 projecting to the basal vertical lobe; and (4) a multiglomerular projection neuron invading the anterior calyx and the lateral horn (TH-MPN). We previously proposed a model in the field cricket in which the efficiency of synapses from Kenyon cells transmitting a relevant sensory stimulus to output neurons commanding an appropriate behavioral reaction can be modified by dopaminergic neurons mediating aversive signals and here, we provide putative neural substrates for the cricket's aversive learning. These will be instrumental in understanding the principle of aversive memory formation in this model species.
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Affiliation(s)
- Yoshitaka Hamanaka
- Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.
- Laboratory of Animal Physiology, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto-cho, Sumiyoshi-ku, Osaka, 558-8585, Japan.
| | - Makoto Mizunami
- Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
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Mizunami M, Matsumoto Y. Roles of Octopamine and Dopamine Neurons for Mediating Appetitive and Aversive Signals in Pavlovian Conditioning in Crickets. Front Physiol 2017; 8:1027. [PMID: 29311961 PMCID: PMC5733098 DOI: 10.3389/fphys.2017.01027] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/27/2017] [Indexed: 01/09/2023] Open
Abstract
Revealing neural systems that mediate appetite and aversive signals in associative learning is critical for understanding the brain mechanisms controlling adaptive behavior in animals. In mammals, it has been shown that some classes of dopamine neurons in the midbrain mediate prediction error signals that govern the learning process, whereas other classes of dopamine neurons control execution of learned actions. In this review, based on the results of our studies on Pavlovian conditioning in the cricket Gryllus bimaculatus and by referring to the findings in honey bees and fruit-flies, we argue that comparable aminergic systems exist in the insect brain. We found that administrations of octopamine (the invertebrate counterpart of noradrenaline) and dopamine receptor antagonists impair conditioning to associate an olfactory or visual conditioned stimulus (CS) with water or sodium chloride solution (appetitive or aversive unconditioned stimulus, US), respectively, suggesting that specific octopamine and dopamine neurons mediate appetitive and aversive signals, respectively, in conditioning in crickets. These findings differ from findings in fruit-flies. In fruit-flies, appetitive and aversive signals are mediated by different dopamine neuron subsets, suggesting diversity in neurotransmitters mediating appetitive signals in insects. We also found evidences of “blocking” and “auto-blocking” phenomena, which suggested that the prediction error, the discrepancy between actual US and predicted US, governs the conditioning in crickets and that octopamine neurons mediate prediction error signals for appetitive US. Our studies also showed that activations of octopamine and dopamine neurons are needed for the execution of an appetitive conditioned response (CR) and an aversive CR, respectively, and we, thus, proposed that these neurons mediate US prediction signals that drive appetitive and aversive CRs. Our findings suggest that the basic principles of functioning of aminergic systems in associative learning, i.e., to transmit prediction error signals for conditioning and to convey US prediction signals for execution of CR, are conserved among insects and mammals, on account of the fact that the organization of the insect brain is much simpler than that of the mammalian brain. Further investigation of aminergic systems that govern associative learning in insects should lead to a better understanding of commonalities and diversities of computational rules underlying associative learning in animals.
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Affiliation(s)
| | - Yukihisa Matsumoto
- College of Liberal Arts and Science, Tokyo Medical and Dental University, Ichikawa, Japan
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Desmedt L, Baracchi D, Devaud JM, Giurfa M, d'Ettorre P. Aversive learning of odor-heat associations in ants. J Exp Biol 2017; 220:4661-4668. [DOI: 10.1242/jeb.161737] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/27/2017] [Indexed: 11/20/2022]
Abstract
Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region due to their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general.
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Affiliation(s)
- Lucie Desmedt
- Laboratory of Experimental and Comparative Ethology, University of Paris 13, Sorbonne Paris Cité, France
| | - David Baracchi
- Laboratory of Experimental and Comparative Ethology, University of Paris 13, Sorbonne Paris Cité, France
- Research Centre on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Jean-Marc Devaud
- Research Centre on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Martin Giurfa
- Research Centre on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, University of Paris 13, Sorbonne Paris Cité, France
- Research Centre on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
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Context-dependent memory traces in the crab's mushroom bodies: Functional support for a common origin of high-order memory centers. Proc Natl Acad Sci U S A 2016; 113:E7957-E7965. [PMID: 27856766 DOI: 10.1073/pnas.1612418113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hypothesis of a common origin for the high-order memory centers in bilateral animals is based on the evidence that several key features, including gene expression and neuronal network patterns, are shared across several phyla. Central to this hypothesis is the assumption that the arthropods' higher order neuropils of the forebrain [the mushroom bodies (MBs) of insects and the hemiellipsoid bodies (HBs) of crustaceans] are homologous structures. However, even though involvement in memory processes has been repeatedly demonstrated for the MBs, direct proof of such a role in HBs is lacking. Here, through neuroanatomical and immunohistochemical analysis, we identified, in the crab Neohelice granulata, HBs that resemble the calyxless MBs found in several insects. Using in vivo calcium imaging, we revealed training-dependent changes in neuronal responses of vertical and medial lobes of the HBs. These changes were stimulus-specific, and, like in the hippocampus and MBs, the changes reflected the context attribute of the memory trace, which has been envisioned as an essential feature for the HBs. The present study constitutes functional evidence in favor of a role for the HBs in memory processes, and provides key physiological evidence supporting a common origin of the arthropods' high-order memory centers.
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Sugimachi S, Matsumoto Y, Mizunami M, Okada J. Effects of Caffeine on Olfactory Learning in Crickets. Zoolog Sci 2016; 33:513-519. [DOI: 10.2108/zs150209] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Schürmann FW. Fine structure of synaptic sites and circuits in mushroom bodies of insect brains. ARTHROPOD STRUCTURE & DEVELOPMENT 2016; 45:399-421. [PMID: 27555065 DOI: 10.1016/j.asd.2016.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 07/01/2016] [Accepted: 08/05/2016] [Indexed: 06/06/2023]
Abstract
In the insect brain, mushroom bodies represent a prominent central neuropil for multisensory integration and, crucially, for learning and memory. For this reason, special attention has been focused on its small chemical synapses. Early studies on synaptic types and their distribution, using conventional electron microscopy, and recent publications have resolved basic features of synaptic circuits. More recent studies, using experimental methods for resolving neurons, such as immunocytochemistry, genetic labelling, high resolution confocal microscopy and more advanced electron microscopy, have revealed many new details about the fine structure and molecular contents of identifiable neurons of mushroom bodies and has led to more refined modelling of functional organisation. Synaptic circuitries have been described in most detail for the calyces. In contrast, the mushroom bodies' columnar peduncle and lobes have been explored to a lesser degree. In dissecting local microcircuits, the scientist is confronted with complex neuronal compartmentalisation and specific synaptic arrangements. This article reviews classical and modern studies on the fine structure of synapses and their networks in mushroom bodies across several insect species.
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Affiliation(s)
- Friedrich-Wilhelm Schürmann
- Johann-Friedrich-Blumenbach Institut für Zoologie und Anthropologie, Georg-August-University Göttingen, Berlinerstrasse 28, D-37073 Göttingen, Germany.
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Matsumoto Y, Matsumoto CS, Takahashi T, Mizunami M. Activation of NO-cGMP Signaling Rescues Age-Related Memory Impairment in Crickets. Front Behav Neurosci 2016; 10:166. [PMID: 27616985 PMCID: PMC4999442 DOI: 10.3389/fnbeh.2016.00166] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/15/2016] [Indexed: 12/02/2022] Open
Abstract
Age-related memory impairment (AMI) is a common feature and a debilitating phenotype of brain aging in many animals. However, the molecular mechanisms underlying AMI are still largely unknown. The cricket Gryllus bimaculatus is a useful experimental animal for studying age-related changes in learning and memory capability; because the cricket has relatively short life-cycle and a high capability of olfactory learning and memory. Moreover, the molecular mechanisms underlying memory formation in crickets have been examined in detail. In the present study, we trained male crickets of different ages by multiple-trial olfactory conditioning to determine whether AMI occurs in crickets. Crickets 3 weeks after the final molt (3-week-old crickets) exhibited levels of retention similar to those of 1-week-old crickets at 30 min or 2 h after training; however they showed significantly decreased levels of 1-day retention, indicating AMI in long-term memory (LTM) but not in anesthesia-resistant memory (ARM) in olfactory learning of crickets. Furthermore, 3-week-old crickets injected with a nitric oxide (NO) donor, a cyclic GMP (cGMP) analog or a cyclic AMP (cAMP) analog into the hemolymph before conditioning exhibited a normal level of LTM, the same level as that in 1-week-old crickets. The rescue effect by NO donor or cGMP analog injection was absent when the crickets were injected after the conditioning. For the first time, an NO donor and a cGMP analog were found to antagonize the age-related impairment of LTM formation, suggesting that deterioration of NO synthase (NOS) or molecules upstream of NOS activation is involved in brain-aging processes.
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Affiliation(s)
- Yukihisa Matsumoto
- College of Liberal Arts and Science, Tokyo Medical and Dental UniversityIchikawa, Japan; Graduate School of Life Science, Hokkaido UniversitySapporo, Japan
| | | | | | - Makoto Mizunami
- Graduate School of Life Science, Hokkaido University Sapporo, Japan
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Shih CT, Sporns O, Yuan SL, Su TS, Lin YJ, Chuang CC, Wang TY, Lo CC, Greenspan R, Chiang AS. Connectomics-Based Analysis of Information Flow in the Drosophila Brain. Curr Biol 2015; 25:1249-58. [PMID: 25866397 DOI: 10.1016/j.cub.2015.03.021] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 01/30/2023]
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Mizunami M, Hamanaka Y, Nishino H. Toward elucidating diversity of neural mechanisms underlying insect learning. ZOOLOGICAL LETTERS 2015; 1:8. [PMID: 26605053 PMCID: PMC4655456 DOI: 10.1186/s40851-014-0008-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/07/2014] [Indexed: 06/05/2023]
Abstract
Insects are widely used as models to study neural mechanisms of learning and memory. Our recent studies on crickets, together with reports on other insect species, suggest that some fundamental differences exist in neural and molecular mechanisms of learning and memory among different species of insects, particularly between crickets and fruit flies. First, we suggested that in crickets octopamine (OA) and dopamine (DA) neurons convey reward and punishment signals, respectively, in associated learning. On the other hand, it has been reported that in fruit flies different sets of DA neurons convey reward or punishment signals. Secondly, we have suggested that in crickets OA and DA neurons participate in the retrieval of appetitive and aversive memories, respectively, while this is not the case in fruit flies. Thirdly, cyclic AMP signaling is critical for short-term memory formation in fruit flies, but not in crickets. Finally, nitric oxide-cyclic GMP signaling and calcium-calmodulin signaling are critical for long-term memory (LTM) formation in crickets, but such roles have not been reported in fruit flies. Not all of these differences can be ascribed to different experimental methods used in studies. We thus suggest that there are unexpected diversities in basic mechanisms of learning and memory among different insect species, especially between crickets and fruit flies. Studies on a larger number of insect species will help clarify the diversity of learning and memory mechanisms in relation to functional adaptation to the environment and evolutionary history.
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Affiliation(s)
- Makoto Mizunami
- />Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-Ku, Sapporo, 060-0810 Japan
| | - Yoshitaka Hamanaka
- />Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-Ku, Sapporo, 060-0810 Japan
| | - Hiroshi Nishino
- />Research Institute for Electronic Science, Hokkaido University, Kita 12 Nishi 7, Kita-ku, Sapporo, 060-0811 Japan
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Sakurai T, Namiki S, Kanzaki R. Molecular and neural mechanisms of sex pheromone reception and processing in the silkmoth Bombyx mori. Front Physiol 2014; 5:125. [PMID: 24744736 PMCID: PMC3978319 DOI: 10.3389/fphys.2014.00125] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/13/2014] [Indexed: 12/01/2022] Open
Abstract
Male moths locate their mates using species-specific sex pheromones emitted by conspecific females. One striking feature of sex pheromone recognition in males is the high degree of specificity and sensitivity at all levels, from the primary sensory processes to behavior. The silkmoth Bombyx mori is an excellent model insect in which to decipher the underlying mechanisms of sex pheromone recognition due to its simple sex pheromone communication system, where a single pheromone component, bombykol, elicits the full sexual behavior of male moths. Various technical advancements that cover all levels of analysis from molecular to behavioral also allow the systematic analysis of pheromone recognition mechanisms. Sex pheromone signals are detected by pheromone receptors expressed in olfactory receptor neurons in the pheromone-sensitive sensilla trichodea on male antennae. The signals are transmitted to the first olfactory processing center, the antennal lobe (AL), and then are processed further in the higher centers (mushroom body and lateral protocerebrum) to elicit orientation behavior toward females. In recent years, significant progress has been made elucidating the molecular mechanisms underlying the detection of sex pheromones. In addition, extensive studies of the AL and higher centers have provided insights into the neural basis of pheromone processing in the silkmoth brain. This review describes these latest advances, and discusses what these advances have revealed about the mechanisms underlying the specific and sensitive recognition of sex pheromones in the silkmoth.
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Affiliation(s)
- Takeshi Sakurai
- Intelligent Cooperative Systems, Research Center for Advanced Science and Technology, The University of Tokyo Meguro-ku, Japan
| | - Shigehiro Namiki
- Intelligent Cooperative Systems, Research Center for Advanced Science and Technology, The University of Tokyo Meguro-ku, Japan
| | - Ryohei Kanzaki
- Intelligent Cooperative Systems, Research Center for Advanced Science and Technology, The University of Tokyo Meguro-ku, Japan
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Kanzaki R, Minegishi R, Namiki S, Ando N. Insect-machine hybrid system for understanding and evaluating sensory-motor control by sex pheromone in Bombyx mori. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:1037-52. [PMID: 23749329 DOI: 10.1007/s00359-013-0832-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 05/21/2013] [Accepted: 05/25/2013] [Indexed: 11/25/2022]
Abstract
To elucidate the dynamic information processing in a brain underlying adaptive behavior, it is necessary to understand the behavior and corresponding neural activities. This requires animals which have clear relationships between behavior and corresponding neural activities. Insects are precisely such animals and one of the adaptive behaviors of insects is high-accuracy odor source orientation. The most direct way to know the relationships between neural activity and behavior is by recording neural activities in a brain from freely behaving insects. There is also a method to give stimuli mimicking the natural environment to tethered insects allowing insects to walk or fly at the same position. In addition to these methods an 'insect-machine hybrid system' is proposed, which is another experimental system meeting the conditions necessary for approaching the dynamic processing in the brain of insects for generating adaptive behavior. This insect-machine hybrid system is an experimental system which has a mobile robot as its body. The robot is controlled by the insect through its behavior or the neural activities recorded from the brain. As we can arbitrarily control the motor output of the robot, we can intervene at the relationship between the insect and the environmental conditions.
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Affiliation(s)
- Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Meguro-ku, Tokyo, 153-8904, Japan,
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Ito E, Matsuo R, Okada R. Involvement of nitric oxide in memory formation in microbrains. Neurosci Lett 2013; 541:1-3. [PMID: 23473717 DOI: 10.1016/j.neulet.2013.02.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 01/09/2023]
Affiliation(s)
- Etsuro Ito
- Laboratory of Functional Biology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
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Giurfa M. Social learning in insects: a higher-order capacity? Front Behav Neurosci 2012; 6:57. [PMID: 22973211 PMCID: PMC3433704 DOI: 10.3389/fnbeh.2012.00057] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 08/14/2012] [Indexed: 11/13/2022] Open
Affiliation(s)
- Martin Giurfa
- Centre de Recherches sur la Cognition Animale, Université de Toulouse Toulouse, France
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Matsumoto Y, Menzel R, Sandoz JC, Giurfa M. Revisiting olfactory classical conditioning of the proboscis extension response in honey bees: a step toward standardized procedures. J Neurosci Methods 2012; 211:159-67. [PMID: 22960052 DOI: 10.1016/j.jneumeth.2012.08.018] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/16/2012] [Accepted: 08/20/2012] [Indexed: 11/16/2022]
Abstract
The honey bee Apis mellifera has emerged as a robust and influential model for the study of classical conditioning thanks to the existence of a powerful Pavlovian conditioning protocol, the olfactory conditioning of the proboscis extension response (PER). In 2011, the olfactory PER conditioning protocol celebrated its 50 years since it was first introduced by Kimihisa Takeda in 1961. In this protocol, individually harnessed honey bees are trained to associate an odor with sucrose solution. The resulting olfactory learning is fast and induces robust olfactory memories that have been characterized at the behavioral, neuronal and molecular levels. Despite the success of this protocol for studying the bases of learning and memory at these different levels, innumerable procedural variants have arisen throughout the years, which render comparative analyses of behavioral performances difficult. Moreover, because even slight variations in conditioning procedures may introduce significant differences in acquisition and retention performances, we revisit olfactory PER conditioning and define here a standardized framework for experiments using this behavioral protocol. To this end, we present and discuss all the methodological steps and details necessary for successful implementation of olfactory PER conditioning.
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Affiliation(s)
- Yukihisa Matsumoto
- UPS, Research Centre for Animal Cognition, Université de Toulouse, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France
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Iriki A, Taoka M. Triadic (ecological, neural, cognitive) niche construction: a scenario of human brain evolution extrapolating tool use and language from the control of reaching actions. Philos Trans R Soc Lond B Biol Sci 2012; 367:10-23. [PMID: 22106423 PMCID: PMC3223791 DOI: 10.1098/rstb.2011.0190] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Hominin evolution has involved a continuous process of addition of new kinds of cognitive capacity, including those relating to manufacture and use of tools and to the establishment of linguistic faculties. The dramatic expansion of the brain that accompanied additions of new functional areas would have supported such continuous evolution. Extended brain functions would have driven rapid and drastic changes in the hominin ecological niche, which in turn demanded further brain resources to adapt to it. In this way, humans have constructed a novel niche in each of the ecological, cognitive and neural domains, whose interactions accelerated their individual evolution through a process of triadic niche construction. Human higher cognitive activity can therefore be viewed holistically as one component in a terrestrial ecosystem. The brain's functional characteristics seem to play a key role in this triadic interaction. We advance a speculative argument about the origins of its neurobiological mechanisms, as an extension (with wider scope) of the evolutionary principles of adaptive function in the animal nervous system. The brain mechanisms that subserve tool use may bridge the gap between gesture and language—the site of such integration seems to be the parietal and extending opercular cortices.
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Affiliation(s)
- Atsushi Iriki
- Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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Abstract
Variation in learning and memory abilities among closely related species, or even among populations of the same species, has opened research into the relationship between cognition, ecological context and the fitness costs, and benefits of learning and memory. Such research programmes have long been dominated by vertebrate studies and by the assumption of a relationship between cognitive abilities, brain size and metabolic costs. Research on these 'large brained' organisms has provided important insights into the understanding of cognitive functions and their adaptive value. In the present review, we discuss some aspects of the fitness costs of learning and memory by focusing on 'mini-brain' studies. Research on learning and memory in insects has challenged some traditional positions and is pushing the boundaries of our understanding of the evolution of learning and memory.
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Affiliation(s)
- James G Burns
- Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada
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Mizunami M, Matsumoto Y. Roles of aminergic neurons in formation and recall of associative memory in crickets. Front Behav Neurosci 2010; 4:172. [PMID: 21119781 PMCID: PMC2991128 DOI: 10.3389/fnbeh.2010.00172] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 10/19/2010] [Indexed: 02/02/2023] Open
Abstract
We review recent progress in the study of roles of octopaminergic (OA-ergic) and dopaminergic (DA-ergic) signaling in insect classical conditioning, focusing on our studies on crickets. Studies on olfactory learning in honey bees and fruit-flies have suggested that OA-ergic and DA-ergic neurons convey reinforcing signals of appetitive unconditioned stimulus (US) and aversive US, respectively. Our work suggested that this is applicable to olfactory, visual pattern, and color learning in crickets, indicating that this feature is ubiquitous in learning of various sensory stimuli. We also showed that aversive memory decayed much faster than did appetitive memory, and we proposed that this feature is common in insects and humans. Our study also suggested that activation of OA- or DA-ergic neurons is needed for appetitive or aversive memory recall, respectively. To account for this finding, we proposed a model in which it is assumed that two types of synaptic connections are strengthened by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus (CS) to neurons inducing conditioned response and the other being connections from neurons representing CS to OA- or DA-ergic neurons representing appetitive or aversive US, respectively. The former is called stimulus–response (S–R) connection and the latter is called stimulus–stimulus (S–S) connection by theorists studying classical conditioning in vertebrates. Results of our studies using a second-order conditioning procedure supported our model. We propose that insect classical conditioning involves the formation of S–S connection and its activation for memory recall, which are often called cognitive processes.
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Affiliation(s)
- Makoto Mizunami
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.
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Mizunami M, Yamagata N, Nishino H. Alarm pheromone processing in the ant brain: an evolutionary perspective. Front Behav Neurosci 2010; 4:28. [PMID: 20676235 PMCID: PMC2912167 DOI: 10.3389/fnbeh.2010.00028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Accepted: 05/10/2010] [Indexed: 11/13/2022] Open
Abstract
Social insects exhibit sophisticated communication by means of pheromones, one example of which is the use of alarm pheromones to alert nestmates for colony defense. We review recent advances in the understanding of the processing of alarm pheromone information in the ant brain. We found that information about formic acid and n-undecane, alarm pheromone components, is processed in a set of specific glomeruli in the antennal lobe of the ant Camponotus obscuripes. Alarm pheromone information is then transmitted, via projection neurons (PNs), to the lateral horn and the calyces of the mushroom body of the protocerebrum. In the lateral horn, we found a specific area where terminal boutons of alarm pheromone-sensitive PNs are more densely distributed than in the rest of the lateral horn. Some neurons in the protocerebrum responded specifically to formic acid or n-undecane and they may participate in the control of behavioral responses to each pheromone component. Other neurons, especially those originating from the mushroom body lobe, responded also to non-pheromonal odors and may play roles in integration of pheromonal and non-pheromonal signals. We found that a class of neurons receive inputs in the lateral horn and the mushroom body lobe and terminate in a variety of premotor areas. These neurons may participate in the control of aggressive behavior, which is sensitized by alarm pheromones and is triggered by non-pheromonal sensory stimuli associated with a potential enemy. We propose that the alarm pheromone processing system has evolved by differentiation of a part of general odor processing system.
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Affiliation(s)
- Makoto Mizunami
- Graduate School of Life Science, Hokkaido University Sapporo, Japan
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Abstract
Attempts to relate brain size to behaviour and cognition have rarely integrated information from insects with that from vertebrates. Many insects, however, demonstrate that highly differentiated motor repertoires, extensive social structures and cognition are possible with very small brains, emphasising that we need to understand the neural circuits, not just the size of brain regions, which underlie these feats. Neural network analyses show that cognitive features found in insects, such as numerosity, attention and categorisation-like processes, may require only very limited neuron numbers. Thus, brain size may have less of a relationship with behavioural repertoire and cognitive capacity than generally assumed, prompting the question of what large brains are for. Larger brains are, at least partly, a consequence of larger neurons that are necessary in large animals due to basic biophysical constraints. They also contain greater replication of neuronal circuits, adding precision to sensory processes, detail to perception, more parallel processing and enlarged storage capacity. Yet, these advantages are unlikely to produce the qualitative shifts in behaviour that are often assumed to accompany increased brain size. Instead, modularity and interconnectivity may be more important.
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Mizunami M, Unoki S, Mori Y, Hirashima D, Hatano A, Matsumoto Y. Roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in an insect. BMC Biol 2009; 7:46. [PMID: 19653886 PMCID: PMC2729297 DOI: 10.1186/1741-7007-7-46] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 08/04/2009] [Indexed: 11/10/2022] Open
Abstract
Background In insect classical conditioning, octopamine (the invertebrate counterpart of noradrenaline) or dopamine has been suggested to mediate reinforcing properties of appetitive or aversive unconditioned stimulus, respectively. However, the roles of octopaminergic and dopaminergic neurons in memory recall have remained unclear. Results We studied the roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in olfactory and visual conditioning in crickets. We found that pharmacological blockade of octopamine and dopamine receptors impaired aversive memory recall and appetitive memory recall, respectively, thereby suggesting that activation of octopaminergic and dopaminergic neurons and the resulting release of octopamine and dopamine are needed for appetitive and aversive memory recall, respectively. On the basis of this finding, we propose a new model in which it is assumed that two types of synaptic connections are formed by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus to neurons inducing conditioned response and the other being connections from neurons representing conditioned stimulus to octopaminergic or dopaminergic neurons representing appetitive or aversive unconditioned stimulus, respectively. The former is called 'stimulus-response connection' and the latter is called 'stimulus-stimulus connection' by theorists studying classical conditioning in higher vertebrates. Our model predicts that pharmacological blockade of octopamine or dopamine receptors during the first stage of second-order conditioning does not impair second-order conditioning, because it impairs the formation of the stimulus-response connection but not the stimulus-stimulus connection. The results of our study with a cross-modal second-order conditioning were in full accordance with this prediction. Conclusion We suggest that insect classical conditioning involves the formation of two kinds of memory traces, which match to stimulus-stimulus connection and stimulus-response connection. This is the first study to suggest that classical conditioning in insects involves, as does classical conditioning in higher vertebrates, the formation of stimulus-stimulus connection and its activation for memory recall, which are often called cognitive processes.
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Affiliation(s)
- Makoto Mizunami
- Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Japan.
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Mashaly A, Winkler M, Frambach I, Gras H, Schürmann FW. Sprouting interneurons in mushroom bodies of adult cricket brains. J Comp Neurol 2008; 508:153-74. [DOI: 10.1002/cne.21660] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Eberhard WG. Miniaturized orb-weaving spiders: behavioural precision is not limited by small size. Proc Biol Sci 2007; 274:2203-9. [PMID: 17609181 PMCID: PMC2706203 DOI: 10.1098/rspb.2007.0675] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The special problems confronted by very small animals in nervous system design that may impose limitations on their behaviour and evolution are reviewed. Previous attempts to test for such behavioural limitations have suffered from lack of detail in behavioural observations of tiny species and unsatisfactory measurements of their behavioural capacities. This study presents partial solutions to both problems. The orb-web construction behaviour of spiders provided data on the comparative behavioural capabilities of tiny animals in heretofore unparalleled detail; species ranged about five orders of magnitude in weight, from approximately 50-100mg down to some of the smallest spiders known (less than 0.005mg), whose small size is a derived trait. Previous attempts to quantify the 'complexity' of behaviour were abandoned in favour of using comparisons of behavioural imprecision in performing the same task. The prediction of the size limitation hypothesis that very small spiders would have a reduced ability to repeat one particular behaviour pattern precisely was not confirmed. The anatomical and physiological mechanisms by which these tiny animals achieve this precision and the possibility that they are more limited in the performance of higher-order behaviour patterns await further investigation.
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Affiliation(s)
- William G Eberhard
- Smithsonian Tropical Research Institute, and Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica.
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Ao Y, Go VLW, Toy N, Li T, Wang Y, Song MK, Reeve JR, Liu Y, Yang H. Brainstem thyrotropin-releasing hormone regulates food intake through vagal-dependent cholinergic stimulation of ghrelin secretion. Endocrinology 2006; 147:6004-10. [PMID: 16959836 DOI: 10.1210/en.2006-0820] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The brainstem is essential for mediating energetic response to starvation. Brain stem TRH is synthesized in caudal raphe nuclei innervating brainstem and spinal vagal and sympathetic motor neurons. Intracisternal injection (ic) of a stable TRH analog RX77368 (7.5-25 ng) dose-dependently stimulated solid food intake by 2.4- to 3-fold in freely fed rats, an effect that lasted for 3 h. By contrast, RX77368 at 25 ng injected into the lateral ventricle induced a delayed and insignificant orexigenic effect only in the first hour. In pentobarbital-anesthetized rats, RX77368 (50 ng) ic induced a significant bipeak increase in serum total ghrelin levels from the basal of 8.7+/-1.7 ng/ml to 13.4+/-2.4 ng/ml at 30 min and 14.5+/-2.0 ng/ml at 90 min, which was prevented by either bilateral vagotomy (-60 min) or atropine pretreatment (2 mg/kg, -30 min) but magnified by bilateral adrenalectomy (-60 min). TRH analog ic-induced food intake in freely fed rats was abolished by either peripheral atropine or ghrelin receptor antagonist (D-Lys-3)-GHRP-6 (10 micromol/kg) or ic Y1 receptor antagonist 122PU91 (10 nmol/5 microl). Brain stem TRH mRNA and TRH receptor 1 mRNA increased by 57-58 and 33-35% in 24- and 48-h fasted rats and returned to the fed levels after a 3-h refeeding. Natural food intake in overnight fasted rats was significantly reduced by ic TRH antibody, ic Y1 antagonist, and peripheral atropine. These data establish a physiological role of brainstem TRH in vagal-ghrelin-mediated stimulation of food intake, which involves interaction with brainstem Y1 receptors.
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Affiliation(s)
- Yan Ao
- Center for Ulcer Research and Education: Digestive Diseases Research Center, Department of Medicine, University of California Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA
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