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Bratman GN, Bembibre C, Daily GC, Doty RL, Hummel T, Jacobs LF, Kahn PH, Lashus C, Majid A, Miller JD, Oleszkiewicz A, Olvera-Alvarez H, Parma V, Riederer AM, Sieber NL, Williams J, Xiao J, Yu CP, Spengler JD. Nature and human well-being: The olfactory pathway. SCIENCE ADVANCES 2024; 10:eadn3028. [PMID: 38748806 DOI: 10.1126/sciadv.adn3028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/12/2024] [Indexed: 07/04/2024]
Abstract
The world is undergoing massive atmospheric and ecological change, driving unprecedented challenges to human well-being. Olfaction is a key sensory system through which these impacts occur. The sense of smell influences quality of and satisfaction with life, emotion, emotion regulation, cognitive function, social interactions, dietary choices, stress, and depressive symptoms. Exposures via the olfactory pathway can also lead to (anti-)inflammatory outcomes. Increased understanding is needed regarding the ways in which odorants generated by nature (i.e., natural olfactory environments) affect human well-being. With perspectives from a range of health, social, and natural sciences, we provide an overview of this unique sensory system, four consensus statements regarding olfaction and the environment, and a conceptual framework that integrates the olfactory pathway into an understanding of the effects of natural environments on human well-being. We then discuss how this framework can contribute to better accounting of the impacts of policy and land-use decision-making on natural olfactory environments and, in turn, on planetary health.
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Affiliation(s)
- Gregory N Bratman
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA
| | - Cecilia Bembibre
- Institute for Sustainable Heritage, University College London, London, UK
| | - Gretchen C Daily
- Natural Capital Project, Stanford University, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Woods Institute, Stanford University, Stanford, CA 94305, USA
| | - Richard L Doty
- Smell and Taste Center, Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thomas Hummel
- Interdisciplinary Center Smell and Taste, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Lucia F Jacobs
- Department of Psychology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Peter H Kahn
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Connor Lashus
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA
| | - Asifa Majid
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | | | - Anna Oleszkiewicz
- Interdisciplinary Center Smell and Taste, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Institute of Psychology, University of Wroclaw, Wrocław, Poland
| | | | | | - Anne M Riederer
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA
| | - Nancy Long Sieber
- T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA
| | - Jonathan Williams
- Air Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
- Climate and Atmosphere Research Center, The Cyprus Institute, Nicosia, Cyprus
| | - Jieling Xiao
- College of Architecture, Birmingham City University, Birmingham, UK
| | - Chia-Pin Yu
- School of Forestry and Resource Conservation, National Taiwan University, Taiwan
- The Experimental Forest, College of Bio-Resources and Agriculture, National Taiwan University, Taiwan
| | - John D Spengler
- T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA
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2
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Williams E, Pauley A, Dewan A. The behavioral sensitivity of mice to acyclic, monocyclic, and bicyclic monoterpenes. PLoS One 2024; 19:e0298448. [PMID: 38394306 PMCID: PMC10890753 DOI: 10.1371/journal.pone.0298448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
Monoterpenes are a large class of naturally occurring fragrant molecules. These chemicals are commonly used in olfactory studies to survey neural activity and probe the behavioral limits of odor discrimination. Monoterpenes (typically in the form of essential oils) have been used for centuries for therapeutic purposes and have pivotal roles in various biological and medical applications. Despite their importance for multiple lines of research using rodent models and the role of the olfactory system in detecting these volatile chemicals, the murine sensitivity to monoterpenes remains mostly unexplored. We assayed the ability of C57BL/6J mice to detect nine different monoterpenes (the acyclic monoterpenes: geraniol, citral, and linalool; the monocyclic monoterpenes: r-limonene, s-limonene, and γ-terpinene; and the bicyclic monoterpenes: eucalyptol, α-pinene, and β-pinene) using a head-fixed Go / No-Go operant conditioning assay. We found that mice can reliably detect monoterpene concentrations in the low parts per billion (ppb) range. Specifically, mice were most sensitive to geraniol (threshold: 0.7 ppb) and least sensitive to γ-terpinene (threshold: 18.1 ppb). These estimations of sensitivity serve to set the lower limit of relevant monoterpene concentrations for functional experiments in mice. To define an upper limit, we estimated the maximum concentrations that a mouse may experience in nature by collating published headspace analyses of monoterpene concentrations emitted from natural sources. We found that natural monoterpenes concentrations typically ranged from ~1 to 1000 ppb. It is our hope that this dataset will help researchers use appropriate monoterpene concentrations for functional studies and provide context for the vapor-phase delivery of these chemicals in studies investigating their biological activity in mice.
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Affiliation(s)
- Ellie Williams
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL, United States of America
| | - Austin Pauley
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL, United States of America
| | - Adam Dewan
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL, United States of America
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3
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Martinez Q, Amson E, Laska M. Does the number of functional olfactory receptor genes predict olfactory sensitivity and discrimination performance in mammals? J Evol Biol 2024; 37:238-247. [PMID: 38297391 DOI: 10.1093/jeb/voae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 12/05/2023] [Accepted: 01/04/2024] [Indexed: 02/02/2024]
Abstract
The number of functional genes coding for olfactory receptors differs markedly between species and has repeatedly been suggested to be predictive of a species' olfactory capabilities. To test this assumption, we compiled a database of all published olfactory detection threshold values in mammals and used three sets of data on olfactory discrimination performance that employed the same structurally related monomolecular odour pairs with different mammal species. We extracted the number of functional olfactory receptor genes of the 20 mammal species for which we found data on olfactory sensitivity and/or olfactory discrimination performance from the Chordata Olfactory Receptor Database. We found that the overall olfactory detection thresholds significantly correlate with the number of functional olfactory receptor genes. Similarly, the overall proportion of successfully discriminated monomolecular odour pairs significantly correlates with the number of functional olfactory receptor genes. These results provide the first statistically robust evidence for the relationship between olfactory capabilities and their genomics correlates. However, when analysed individually, of the 44 monomolecular odourants for which data on olfactory sensitivity from at least five mammal species are available, only five yielded a significant correlation between olfactory detection thresholds and the number of functional olfactory receptors genes. Also, for the olfactory discrimination performance, no significant correlation was found for any of the 74 relationships between the proportion of successfully discriminated monomolecular odour pairs and the number of functional olfactory receptor genes. While only a rather limited amount of data on olfactory detection thresholds and olfactory discrimination scores in a rather limited number of mammal species is available so far, we conclude that the number of functional olfactory receptor genes may be a predictor of olfactory sensitivity and discrimination performance in mammals.
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Affiliation(s)
| | - Eli Amson
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
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Abstract
Historically, the human sense of smell has been regarded as the odd stepchild of the senses, especially compared to the sensory bravado of seeing, touching, and hearing. The idea that the human olfaction has little to contribute to our experience of the world is commonplace, though with the emergence of COVID-19 there has rather been a sea change in this understanding. An ever increasing body of work has convincingly highlighted the keen capabilities of the human nose and the sophistication of the human olfactory system. Here, we provide a concise overview of the neuroscience of human olfaction spanning the last 10-15 years, with focus on the peripheral and central mechanisms that underlie how odor information is processed, packaged, parceled, predicted, and perturbed to serve odor-guided behaviors. We conclude by offering some guideposts for harnessing the next decade of olfactory research in all its shapes and forms.
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Affiliation(s)
| | - Jay A Gottfried
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Villalobos A, Schlyter F, Birgersson G, Koteja P, Löf M. Fear effects on bank voles (Rodentia: Arvicolinae): testing for repellent candidates from predator volatiles. PEST MANAGEMENT SCIENCE 2022; 78:1677-1685. [PMID: 34994055 PMCID: PMC9306653 DOI: 10.1002/ps.6787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/23/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Arvicolinae rodents are known pests causing damage to both agricultural and forest crops. Today, rodenticides for rodent control are widely discouraged owing to their negative effects on the environment. Rodents are the main prey for several predators, and their complex olfactory system allows them to identify risks of predation. Therefore, the potential use of predators' scents as repellents has gained interest as an ecologically based rodent control method. In a two-choice experiment, we investigated the potential repellent effects of five synthetic predator compounds: 2-phenylethylamine (2-PEA), 2-propylthietane (2-PT), indole, heptanal and 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), at 1% and 5% doses, using the bank vole (Myodes glareolus) as a rodent model. RESULTS The compound 2-PEA reduced both the food contacts and the time spent by voles in the treatment arm compared to the control arm. Likewise, 2-PT-treated arms reduced the food contacts, and the voles spent less time there, although this latter difference was not significant. Indole also showed a tendency to reduce the time spent at the treatment arm; however, this result was not significant. Unexpectedly, TMT had the reverse effect in showing attractive properties, possibly due to odor cues from differently sized predators and intraguild predation in nature. We found no dose-related effects for any compounds tested. CONCLUSION Our results suggest that the 2-PEA and 2-PT are both effective odor stimuli for triggering reduced food contacts and area avoidance, and they may be good repellent candidates. We suggest further testing of 2-PEA and 2-PT in field experiments to further determine their dose-efficiency as repellents against rodents in more natural environments. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Adrian Villalobos
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesLommaSweden
- Büsgen‐Institute, Department of Forest Zoology and Forest ConservationGeorg‐August‐Universität GöttingenGöttingenGermany
| | - Fredrik Schlyter
- Department of Plant Protection BiologySwedish University of Agricultural SciencesLommaSweden
- Excellent Team for Mitigation, Faculty of Forestry & Wood SciencesCzech University of Life Sciences PragueSuchdolCzech Republic
| | - Göran Birgersson
- Department of Plant Protection BiologySwedish University of Agricultural SciencesLommaSweden
| | - Paweł Koteja
- Institute of Environmental SciencesJagiellonian UniversityKrakówPoland
| | - Magnus Löf
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesLommaSweden
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6
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Ability of dog owners to identify their dogs by smell. Sci Rep 2021; 11:22784. [PMID: 34815506 PMCID: PMC8610967 DOI: 10.1038/s41598-021-02238-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 11/11/2021] [Indexed: 11/08/2022] Open
Abstract
Several studies report that olfactory cues play an important role in human life; humans are essentially able to recognize other family members and friends by their odors. Moreover, recent studies report that humans are also able to identify odors of non-conspecifics. The aim of this study was to determine whether dog owners are able to identify their dogs by smell and distinguish the odor of their own dogs from those of other dogs. A total of 53 dog owners (40 females and 13 males of different ages) volunteered to take part in this study. A number of the participants (17) owned 2 dogs; these owners took part in the study twice (i.e., working with only one dog at a time). Sterile gauze pads were used to collect odor samples from the dogs. Each pad was placed in its own sterile glass jar (750 ml) with a twist off lid until the experiment commenced. Participants were asked to identify their own dog´s odor from a line-up of 6 glass containers. This experiment demonstrated that dog owners are capable of identifying their dogs by smell on a significant level. Results of this study additionally suggested that male owners outperformed their female counterparts in the identification process. Moreover, dog owners whose dogs were housed outside had a higher success rate in identification than did participants who kept their dogs indoors with them. The dog owners found it easier to identify dogs that had been neutered, fed dry dog food and bathed less frequently. In general, younger dog owners tended to have more success when attempting to identify their dogs than did their older counterparts.
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AlMatrouk A, Lemons K, Ogura T, Lin W. Modification of the Peripheral Olfactory System by Electronic Cigarettes. Compr Physiol 2021; 11:2621-2644. [PMID: 34661289 DOI: 10.1002/cphy.c210007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electronic cigarettes (e-cigs) are used by millions of adolescents and adults worldwide. Commercial e-liquids typically contain flavorants, propylene glycol, and vegetable glycerin with or without nicotine. These chemical constituents are detected and evaluated by chemosensory systems to guide and modulate vaping behavior and product choices of e-cig users. The flavorants in e-liquids are marketing tools. They evoke sensory percepts of appealing flavors through activation of chemical sensory systems to promote the initiation and sustained use of e-cigs. The vast majority of flavorants in e-liquids are volatile odorants, and as such, the olfactory system plays a dominant role in perceiving these molecules that enter the nasal cavity either orthonasally or retronasally during vaping. In addition to flavorants, e-cig aerosol contains a variety of by-products generated through heating the e-liquids, including odorous irritants, toxicants, and heavy metals. These harmful substances can directly and adversely impact the main olfactory epithelium (MOE). In this article, we first discuss the olfactory contribution to e-cig flavor perception. We then provide information on MOE cell types and their major functions in olfaction and epithelial maintenance. Olfactory detection of flavorants, nicotine, and odorous irritants and toxicants are also discussed. Finally, we discuss the cumulated data on modification of the MOE by flavorant exposure and toxicological impacts of formaldehyde, acrolein, and heavy metals. Together, the information presented in this overview may provide insight into how e-cig exposure may modify the olfactory system and adversely impact human health through the alteration of the chemosensory factor driving e-cig use behavior and product selections. © 2021 American Physiological Society. Compr Physiol 11:2621-2644, 2021.
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Affiliation(s)
- Abdullah AlMatrouk
- General Department of Criminal Evidence, Forensic Laboratories, Ministry of Interior, Farwaniyah, Kuwait.,Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Kayla Lemons
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA.,Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
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8
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Butruille L, Vancamp P, Demeneix BA, Remaud S. Thyroid hormone regulation of adult neural stem cell fate: A comparative analysis between rodents and primates. VITAMINS AND HORMONES 2021; 116:133-192. [PMID: 33752817 DOI: 10.1016/bs.vh.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Thyroid hormone (TH) signaling, a highly conserved pathway across vertebrates, is crucial for brain development and function throughout life. In the adult mammalian brain, including that of humans, multipotent neural stem cells (NSCs) proliferate and generate neuronal and glial progenitors. The role of TH has been intensively investigated in the two main neurogenic niches of the adult mouse brain, the subventricular and the subgranular zone. A key finding is that T3, the biologically active form of THs, promotes NSC commitment toward a neuronal fate. In this review, we first discuss the roles of THs in the regulation of adult rodent neurogenesis, as well as how it relates to functional behavior, notably olfaction and cognition. Most research uncovering these roles of TH in adult neurogenesis was conducted in rodents, whose genetic background, brain structure and rate of neurogenesis are considerably different from that of humans. To bridge the phylogenetic gap, we also explore the similarities and divergences of TH-dependent adult neurogenesis in non-human primate models. Lastly, we examine how photoperiodic length changes TH homeostasis, and how that might affect adult neurogenesis in seasonal species to increase fitness. Several aspects by which TH acts on adult NSCs seem to be conserved among mammals, while we only start to uncover the molecular pathways, as well as how other in- and extrinsic factors are intertwined. A multispecies approach delivering more insights in the matter will pave the way for novel NSC-based therapies to combat neurological disorders.
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Affiliation(s)
- Lucile Butruille
- UMR 7221 Phyma, CNRS/Muséum National d'Histoire Naturelle, Paris, France
| | - Pieter Vancamp
- UMR 7221 Phyma, CNRS/Muséum National d'Histoire Naturelle, Paris, France
| | - Barbara A Demeneix
- UMR 7221 Phyma, CNRS/Muséum National d'Histoire Naturelle, Paris, France
| | - Sylvie Remaud
- UMR 7221 Phyma, CNRS/Muséum National d'Histoire Naturelle, Paris, France.
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Uselman TW, Barto DR, Jacobs RE, Bearer EL. Evolution of brain-wide activity in the awake behaving mouse after acute fear by longitudinal manganese-enhanced MRI. Neuroimage 2020; 222:116975. [PMID: 32474079 PMCID: PMC7805483 DOI: 10.1016/j.neuroimage.2020.116975] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 01/08/2023] Open
Abstract
Life threatening fear after a single exposure evolves in a subset of vulnerable individuals to anxiety, which may persist for their lifetime. Yet neither the whole brain's response to innate acute fear nor how brain activity evolves over time is known. Sustained neuronal activity may be a factor in the development of a persistent fear response. We couple two experimental protocols to provoke acute fear leading to prolonged fear: Predator stress (PS), a naturalistic approach to induce fear in rodents; and Serotonin transporter knockout mouse (SERT-KO) that responds to PS with sustained defensive behavior. Behavior was monitored before, during and at short and long times after PS in wild type (WT) and SERT-KO mice. Both genotypes responded to PS with defensive behavior. SERT-KO retained defensive behavior for 23 days, while WT mice returned to baseline exploratory behavior by 9 days. Thus, differences in neural activity between WT and SERT-KO 9 days after PS identifies neural correlates of persistent defensive behavior, in mice. We used longitudinal manganese-enhanced magnetic resonance imaging (MEMRI) to identify brain-wide neural activity associated with different behaviors. Mn2+ accumulation in active neurons occurs in awake, behaving mice and is retrospectively imaged. Following the same two cohorts of mice, WT and SERT-KO, longitudinally allowed unbiased quantitative comparisons of brain-wide activity by statistical parametric mapping (SPM). During natural behavior in WT, only low levels of activity-induced Mn2+-accumulation were detected, while much more accumulation appeared immediately after PS in both WT and SERT-KO, and evolved at 9 days to a new activity pattern (p < 0.0001, uncorr., T = 5.4). Patterns of accumulation differed between genotypes, with more regions of the brain and larger volumes within regions involved in SERT-KO than WT. A new computational segmentation analysis, using our InVivo Atlas based on a manganese-enhanced MR image of a living mouse, revealed dynamic changes in the volume of significantly enhanced voxels within each segment that differed between genotypes across 45 of 87 segmented regions. At Day 9 after PS, the striatum and ventral pallidum were active in both genotypes but more so in the SERT-KO. SERT-KO also displayed sustained or increased volume of Mn2+ accumulations between Post-Fear and Day 9 in eight segments where activity was decreased or silenced in WT. C-fos staining, an alternative neural activity marker, of brains from the same mice fixed at conclusion of imaging sessions confirmed that MEMRI detected active neurons. Intensity measurements in 12 regions of interest (ROIs) supported the SPM results. Between group comparisons by SPM and of ROI measurements identified specific regions differing between time points and genotypes. We report brain-wide activity in response to a single exposure of acute fear, and, for the first time, its evolution to new activity patterns over time in individuals vulnerable to persistent fear. Our results show multiple regions with dynamic changes in neural activity and that the balance of activity between segments is disordered in the SERT-KO. Thus, longitudinal MEMRI represents a powerful approach to discover how brain-wide activity evolves from the natural state either after an experience or during a disease process.
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Affiliation(s)
- Taylor W Uselman
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Daniel R Barto
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Russell E Jacobs
- Zilkha Neurogenetics Institute, University of Southern California, Los Angeles, CA, USA; California Institute of Technology, Pasadena, CA, USA
| | - Elaine L Bearer
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA; California Institute of Technology, Pasadena, CA, USA.
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10
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Application of Pharmacokinetic-Pharmacodynamic Modeling to Inform Translation of In Vitro NaV1.7 Inhibition to In Vivo Pharmacological Response in Non-human Primate. Pharm Res 2020; 37:181. [PMID: 32888082 PMCID: PMC7473964 DOI: 10.1007/s11095-020-02914-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/18/2020] [Indexed: 12/25/2022]
Abstract
Purpose This work describes a staged approach to the application of pharmacokinetic-pharmacodynamic (PK-PD) modeling in the voltage-gated sodium ion channel (NaV1.7) inhibitor drug discovery effort to address strategic questions regarding in vitro to in vivo translation of target modulation. Methods PK-PD analysis was applied to data from a functional magnetic resonance imaging (fMRI) technique to non-invasively measure treatment mediated inhibition of olfaction signaling in non-human primates (NHPs). Initial exposure-response was evaluated using single time point data pooled across 27 compounds to inform on in vitro to in vivo correlation (IVIVC). More robust effect compartment PK-PD modeling was conducted for a subset of 10 compounds with additional PD and PK data to characterize hysteresis. Results The pooled compound exposure-response facilitated an early exploration of IVIVC with a limited dataset for each individual compound, and it suggested a 2.4-fold in vitro to in vivo scaling factor for the NaV1.7 target. Accounting for hysteresis with an effect compartment PK-PD model as compounds advanced towards preclinical development provided a more robust determination of in vivo potency values, which resulted in a statistically significant positive IVIVC with a slope of 1.057 ± 0.210, R-squared of 0.7831, and p value of 0.006. Subsequent simulations with the PK-PD model informed the design of anti-nociception efficacy studies in NHPs. Conclusions A staged approach to PK-PD modeling and simulation enabled integration of in vitro NaV1.7 potency, plasma protein binding, and pharmacokinetics to describe the exposure-response profile and inform future study design as the NaV1.7 inhibitor effort progressed through drug discovery. Electronic supplementary material The online version of this article (10.1007/s11095-020-02914-9) contains supplementary material, which is available to authorized users.
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11
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Taylor JE, Lau H, Seymour B, Nakae A, Sumioka H, Kawato M, Koizumi A. An Evolutionarily Threat-Relevant Odor Strengthens Human Fear Memory. Front Neurosci 2020; 14:255. [PMID: 32425741 PMCID: PMC7212458 DOI: 10.3389/fnins.2020.00255] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/06/2020] [Indexed: 11/13/2022] Open
Abstract
Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influence routine human behavior. We examined whether a threat-relevant predator odor (2-methyl-2-thiazoline) would contextually enhance the formation of human fear memory associations. Participants who learned to associate visual stimuli with electric shock in this predator odor context later showed stronger fear responses to the visual stimuli than participants who learned in an aversiveness-matched control odor context. This effect generalized to testing in another odor context, even after extinction training. Results of a separate experiment indicate that a possible biological mechanism for this effect may be increased cortisol levels in a predator odor context. These results suggest that innate olfactory processes can play an important role in human fear learning. Modulatory influences of odor contexts may partly explain the sometimes maladaptive persistence of human fear memory, e.g., in post-traumatic stress disorders.
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Affiliation(s)
- Jessica E Taylor
- Department of Decoded Neurofeedback (DecNef), Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Hakwan Lau
- Department of Decoded Neurofeedback (DecNef), Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan.,Department of Psychology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Psychology, University of Hong Kong, Pokfulam, Hong Kong
| | - Ben Seymour
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Osaka, Japan.,Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge, United Kingdom.,Department of Neural Computation for Decision-Making, Cognitive Mechanisms Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Aya Nakae
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Hidenobu Sumioka
- Hiroshi Ishiguro Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Mitsuo Kawato
- Department of Decoded Neurofeedback (DecNef), Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan.,Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Osaka, Japan
| | - Ai Koizumi
- Department of Decoded Neurofeedback (DecNef), Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan.,Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Osaka, Japan.,Sony Computer Science Laboratories, Inc., Tokyo, Japan
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12
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Cho SW, Park TH. Comparative Evaluation of Sensitivity to Hexanal Between Human and Canine Olfactory Receptors. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0265-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Wester P, Johnson SD, Pauw A. Scent chemistry is key in the evolutionary transition between insect and mammal pollination in African pineapple lilies. THE NEW PHYTOLOGIST 2019; 222:1624-1637. [PMID: 30613998 DOI: 10.1111/nph.15671] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/31/2018] [Indexed: 06/09/2023]
Abstract
Volatile emissions may play a key role in structuring pollination systems of plants with morphologically unspecialised flowers. Here we test for pollination by small mammals in Eucomis regia and investigate whether its floral scent differs markedly from fly- and wasp-pollinated congeners and attracts mammals. We measured floral traits of E. regia and made comparisons with insect-pollinated congeners. We observed floral visitors and examined fur and faeces of live-trapped mammals for pollen. We determined the contributions of different floral visitors to seed set with selective exclusion and established the breeding system with controlled pollination experiments. Using bioassays, we examined whether mammals are attracted by the floral scent and are effective agents of pollen transfer. Eucomis regia differs from closely related insect-pollinated species mainly in floral scent, with morphology, colour and nectar properties being similar. We found that mice and elephant-shrews pollinate E. regia, which is self-incompatible and reliant on vertebrates for seed production. Mammals are strongly attracted to the overall floral scent, which contains unusual sulphur compounds, including methional (which imparts the distinctive potato-like scent and which was shown to be attractive to small mammals). The results highlight the important role of scent chemistry in shifts between insect and mammal pollination systems.
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Affiliation(s)
- Petra Wester
- School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
- Institute of Sensory Ecology, Heinrich-Heine-University, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Steven D Johnson
- School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa
| | - Anton Pauw
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
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14
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Block E. Molecular Basis of Mammalian Odor Discrimination: A Status Report. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13346-13366. [PMID: 30453735 DOI: 10.1021/acs.jafc.8b04471] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Humans have 396 unique, intact olfactory receptors (ORs), G-protein coupled receptors (GPCRs) containing receptor-specific binding sites; other mammals have more. Activation of these transmembrane proteins by an odorant initiates a signaling cascade, evoking an action potential leading to perception of a smell. Because the number of distinguishable odorants vastly exceeds the number of ORs, research has focused on mechanisms of recognition and signaling processes for classes of odorants. In this review, selected recent examples will be presented of "deorphaned" mammalian receptors, where the OR ligands (odorants) as well as key aspects of receptor-odorant interactions were identified using odorant-mediated receptor activation data together with site-directed mutagenesis and molecular modeling. Based on cumulative evidence from OR deorphaning and olfactory receptor neuron activation studies, a receptor-ligand docking model rather than an alternative bond vibration model is suggested to best explain the molecular basis of the exquisitely sensitive odor discrimination in mammals.
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Affiliation(s)
- Eric Block
- Department of Chemistry , University at Albany, SUNY , Albany , New York 12222 , United States
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15
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Courtens F, Demangeat JL, Benabdallah M. Could the Olfactory System Be a Target for Homeopathic Remedies as Nanomedicines? J Altern Complement Med 2018; 24:1032-1038. [PMID: 29889551 PMCID: PMC6247980 DOI: 10.1089/acm.2018.0039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Homeopathic remedies (HRs) contain odorant molecules such as flavonoids or terpenes and can lose their efficiency in presence of some competitive odors. Such similarities, along with extreme sensitivity of the olfactory system, widespread presence of olfactory receptors over all organic tissues (where they have metabolic roles besides perception of odors), and potential direct access to the brain through olfactory nerves (ONs) and trigeminal nerves, may suggest the olfactory system as target for HRs. Recent works highlighted that HRs exist in a dual form, that is, a still molecular form at low dilution and a nanoparticulate form at high dilution, and that remnants of source remedy persist in extremely high dilutions. From the literature, both odorants and nanoparticles (NPs) can enter the body through inhalation, digestive absorption, or through the skin, especially, NPs or viruses can directly reach the brain through axons of nerves. Assuming that HRs are recognized by olfactory receptors, their information could be transmitted to numerous tissues through receptor-ligand interaction, or to the brain by either activating the axon potential of ONs and trigeminal nerves or, in their nanoparticulate form, by translocating through axons of these nerves. Moreover, the nanoparticulate form may activate the immune system at multiple levels, induce systemic various biological responses through the pituitary axis and inflammation factors, or modulate gene expression at the cellular level. As immunity, inflammation, pituitary axis, and olfactory system are closely linked together, their permanent interaction triggered by olfactory receptors may thus ensure homeostasis.
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16
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Peixoto L, Salazar LTH, Laska M. Olfactory sensitivity for mold-associated odorants in CD-1 mice and spider monkeys. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:821-833. [PMID: 30203157 PMCID: PMC6182676 DOI: 10.1007/s00359-018-1285-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 08/24/2018] [Accepted: 09/01/2018] [Indexed: 12/30/2022]
Abstract
Using operant conditioning procedures, we assessed the olfactory sensitivity of six CD-1 mice and three spider monkeys for mold-associated odorants. We found that with all eight stimuli, the mice detected concentrations as low as 0.1 ppm (parts per million), and with two of them individual animals even detected concentrations as low as 1 ppt (parts per trillion). The spider monkeys detected concentrations as low as 4 ppm with all eight stimuli, and with four of them individual animals even detected concentrations as low as 4 ppb (parts per billion). Between-species comparisons showed that with all eight odorants, the mice displayed significantly lower threshold values, that is, a higher sensitivity than the spider monkeys, but not than human subjects tested in previous studies. Analysis of odor structure–activity relationships showed that in both species, the type of oxygen-containing functional group and the presence versus absence of a double bond as well as the length of the carbon backbone of the odor stimuli had a systematic effect on detectability. We conclude that both mice and spider monkeys are clearly able to detect the presence of molds and thus to assess the palatability of potential food using the volatiles produced by molds during putrefaction.
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Affiliation(s)
- Luis Peixoto
- IFM Biology, Linköping University, 581 83, Linköping, Sweden
| | | | - Matthias Laska
- IFM Biology, Linköping University, 581 83, Linköping, Sweden.
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17
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Pettersson H, Amundin M, Laska M. Attractant or Repellent? Behavioral Responses to Mammalian Blood Odor and to a Blood Odor Component in a Mesopredator, the Meerkat ( Suricata suricatta). Front Behav Neurosci 2018; 12:152. [PMID: 30083096 PMCID: PMC6064876 DOI: 10.3389/fnbeh.2018.00152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 07/03/2018] [Indexed: 12/04/2022] Open
Abstract
It is well-established that the odor of mammalian blood is attractive to top predators such as tigers and wolves and aversive to prey species such as mice and rats. Recent studies have shown that the mammalian blood odor component trans-4,5-epoxy-(E)-2-decenal (TED) elicits corresponding behavioral responses in these two groups of mammals. Here we assess whether a mesopredator, that is, a small-bodied carnivorous mammal that is both predator and prey, is attracted to or repelled by the odor of mammalian blood and TED. To this end, we assessed the behavior of a group of 15 captive meerkats (Suricata suricatta) when presented with wooden logs that were impregnated either with horse blood or with TED, and compared it to their behavior toward a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate). We found that the meerkats displayed significantly more interactions with the odorized wooden logs such as sniffing and pawing when these were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant difference was found in the number of interactions with the wooden logs impregnated with horse blood and TED, respectively. These results demonstrate that meerkats, despite being small-bodied mesopredators, are clearly attracted to the odor of mammalian blood. Further, the results suggest that a single blood odor component can be as efficient as the odor of real blood in eliciting behavioral responses in this herpestid mammal, similar to previous findings in feline and canine top predators.
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Affiliation(s)
- Henrik Pettersson
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Mats Amundin
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Kolmården Wildlife Park, Kolmården, Sweden
| | - Matthias Laska
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
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18
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Zhao F, Holahan MA, Wang X, Uslaner JM, Houghton AK, Evelhoch JL, Winkelmann CT, Hines CDG. fMRI study of the role of glutamate NMDA receptor in the olfactory processing in monkeys. PLoS One 2018; 13:e0198395. [PMID: 29870538 PMCID: PMC5988321 DOI: 10.1371/journal.pone.0198395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 05/20/2018] [Indexed: 11/24/2022] Open
Abstract
Studies in rodents show that olfactory processing in the principal neurons of olfactory bulb (OB) and piriform cortex (PC) is controlled by local inhibitory interneurons, and glutamate NMDA receptor plays a role in this inhibitory control. It is not clear if findings from studies in rodents translate to olfactory processing in nonhuman primates (NHPs). In this study, the effect of the glutamate NMDA receptor antagonist MK801 on odorant-induced olfactory responses in the OB and PC of anesthetized NHPs (rhesus monkeys) was investigated by cerebral blood volume (CBV) fMRI. Isoamyl-acetate was used as the odor stimulant. For each NHP, sixty fMRI measurements were made during a 4-h period, with each 4-min measurement consisting of a 1-min baseline period, a 1-min odor stimulation period, and a 2-min recovery period. MK801 (0.3 mg/kg) was intravenously delivered 1 hour after starting fMRI. Before MK801 injection, olfactory fMRI activations were observed only in the OB, not in the PC. After MK801 injection, olfactory fMRI activations in the OB increased, and robust olfactory fMRI activations were observed in the PC. The data indicate that MK801 enhances the olfactory responses in both the OB and PC. The enhancement effects of MK801 are most likely from its blockage of NMDA receptors on local inhibitory interneurons and the attenuation of the inhibition onto principal neurons. This study suggests that the mechanism of local inhibitory control of principal neurons in the OB and PC derived from studies in rodents translates to NHPs.
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Affiliation(s)
- Fuqiang Zhao
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
- * E-mail:
| | - Marie A. Holahan
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Xiaohai Wang
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Jason M. Uslaner
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
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19
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Abstract
It is commonly believed that humans have a poor sense of smell compared to other mammalian species. However, this idea derives not from empirical studies of human olfaction but from a famous 19th-century anatomist's hypothesis that the evolution of human free will required a reduction in the proportional size of the brain's olfactory bulb. The human olfactory bulb is actually quite large in absolute terms and contains a similar number of neurons to that of other mammals. Moreover, humans have excellent olfactory abilities. We can detect and discriminate an extraordinary range of odors, we are more sensitive than rodents and dogs for some odors, we are capable of tracking odor trails, and our behavioral and affective states are influenced by our sense of smell.
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Affiliation(s)
- John P McGann
- Behavioral and Systems Neuroscience, Psychology Department, Rutgers University, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA.
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20
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Block E, Batista VS, Matsunami H, Zhuang H, Ahmed L. The role of metals in mammalian olfaction of low molecular weight organosulfur compounds. Nat Prod Rep 2017; 34:529-557. [PMID: 28471462 PMCID: PMC5542778 DOI: 10.1039/c7np00016b] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Covering: up to the end of 2017While suggestions concerning the possible role of metals in olfaction and taste date back 50 years, only recently has it been possible to confirm these proposals with experiments involving individual olfactory receptors (ORs). A detailed discussion of recent experimental results demonstrating the key role of metals in enhancing the response of human and other vertebrate ORs to specific odorants is presented against the backdrop of our knowledge of how the sense of smell functions both at the molecular and whole animal levels. This review emphasizes the role of metals in the detection of low molecular weight thiols, sulfides, and other organosulfur compounds, including those found in strong-smelling animal excretions and plant volatiles, and those used in gas odorization. Alternative theories of olfaction are described, with evidence favoring the modified "shape" theory. The use of quantum mechanical/molecular modeling (QM/MM), site-directed mutagenesis and saturation-transfer-difference (STD) NMR is discussed, providing support for biological studies of mouse and human receptors, MOR244-3 and OR OR2T11, respectively. Copper is bound at the active site of MOR244-3 by cysteine and histidine, while cysteine, histidine and methionine are involved with OR2T11. The binding pockets of these two receptors are found in different locations in the three-dimensional seven transmembrane models. Another recently deorphaned human olfactory receptor, OR2M3, highly selective for a thiol from onions, and a broadly-tuned thiol receptor, OR1A1, are also discussed. Other topics covered include the effects of nanoparticles and heavy metal toxicants on vertebrate and fish ORs, intranasal zinc products and the loss of smell (anosmia).
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Affiliation(s)
- Eric Block
- Department of Chemistry, University at Albany, State University of New York, Albany, New York 12222, USA.
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21
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Osada K, Miyazono S, Kashiwayanagi M. Structure-Activity Relationships of Alkylpyrazine Analogs and Fear-Associated Behaviors in Mice. J Chem Ecol 2017; 43:263-272. [DOI: 10.1007/s10886-017-0822-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 02/03/2023]
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22
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Population Coding in an Innately Relevant Olfactory Area. Neuron 2017; 93:1180-1197.e7. [PMID: 28238549 DOI: 10.1016/j.neuron.2017.02.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/22/2016] [Accepted: 02/04/2017] [Indexed: 11/23/2022]
Abstract
Different olfactory cortical regions are thought to harbor distinct sensory representations, enabling each area to play a unique role in odor perception and behavior. In the piriform cortex (PCx), spatially dispersed sensory inputs evoke activity in distributed ensembles of neurons that act as substrates for odor learning. In contrast, the posterolateral cortical amygdala (plCoA) receives hardwired inputs that may link specific odor cues to innate olfactory behaviors. Here we show that despite stark differences in the patterning of plCoA and PCx inputs, odor-evoked neural ensembles in both areas are equally capable of discriminating odors, and exhibit similar odor tuning, reliability, and correlation structure. These results demonstrate that brain regions mediating odor-driven innate behaviors can, like brain areas involved in odor learning, represent odor objects using distributive population codes; these findings suggest both alternative mechanisms for the generation of innate odor-driven behaviors and additional roles for the plCoA in odor perception.
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23
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Sarrafchi A, Laska M. Olfactory Sensitivity for the Mammalian Blood Odor Component Trans-4,5-epoxy-(E)-2-decenal in CD-1 Mice. Perception 2016; 46:333-342. [PMID: 27251166 DOI: 10.1177/0301006616653136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Using a conditioning paradigm and an automated olfactometer, we investigated the olfactory sensitivity of CD-1 mice for the mammalian blood odor component trans-4,5-epoxy-(E)-2-decenal. We found that two of the animals significantly discriminated concentrations down to 3.0 ppt (parts per trillion) from the solvent, and three animals even successfully detected dilutions as low as 0.3 ppt. Intraspecific comparisons between the olfactory detection thresholds obtained here with those obtained in earlier studies with other odorants show that mice are extraordinarily sensitive to this blood odor component. Interspecific comparisons of olfactory detection thresholds show that human subjects are even more sensitive to trans-4,5-epoxy-(E)-2-decenal than the mice tested here. Both intra- and inter-specific comparisons suggest that neither neuroanatomical properties such as the size of the olfactory epithelium, the total number of olfactory receptor neurons, or the size of olfactory brain structures, nor genetic properties such as the number of functional olfactory receptor genes or the proportion of functional relative to the total number of olfactory receptor genes allow us to reliably predict a species' olfactory sensitivity. In contrast, the results support the notion that the behavioral relevance of an odorant rather than neuroanatomical or genetic properties may determine a species' olfactory sensitivity.
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24
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Sievert T, Laska M. Behavioral Responses of CD-1 Mice to Six Predator Odor Components. Chem Senses 2016; 41:399-406. [PMID: 26892309 DOI: 10.1093/chemse/bjw015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mammalian prey species are able to detect predator odors and to display appropriate defensive behavior. However, there is only limited knowledge about whether single compounds of predator odors are sufficient to elicit such behavior. Therefore, we assessed if predator-naïve CD-1 mice (n = 60) avoid sulfur-containing compounds that are characteristic components of natural predator odors and/or display other indicators of anxiety. A 2-compartment test arena was used to assess approach/avoidance behavior, general motor activity, and the number of fecal pellets excreted when the animals were presented with 1 of 6 predator odor components in one compartment and a blank control in the other compartment. We found that 2 of the 6 predator odor components (2-propylthietane and 3-methyl-1-butanethiol) were significantly avoided by the mice. The remaining 4 predator odor components (2,2-dimethylthietane, 3-mercapto-3-methylbutan-1-ol, 3-mercapto-3-methylbutyl-1-formate, and methyl-2-phenylethyl sulphide) as well as a nonpredator-associated fruity odor (n-pentyl acetate) were not avoided. Neither the general motor activity nor the number of excreted fecal pellets, both widely used measures of stress- or anxiety-related behavior, were systematically affected by any of the odorants tested. Further, we found that small changes in the molecular structure of a predator odor component can have a marked effect on its behavioral significance as 2-propylthietane was significantly avoided by the mice whereas the structurally related 2,2-dimethylthietane was not. We conclude that sulfur-containing volatiles identified as characteristic components of the urine, feces, and anal gland secretions of mammalian predators can be, but are not necessarily sufficient to elicit defensive behaviors in a mammalian prey species.
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Affiliation(s)
| | - Matthias Laska
- IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
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25
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Chemical recognition of fruit ripeness in spider monkeys (Ateles geoffroyi). Sci Rep 2015; 5:14895. [PMID: 26440380 PMCID: PMC4594300 DOI: 10.1038/srep14895] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/11/2015] [Indexed: 11/20/2022] Open
Abstract
Primates are now known to possess well-developed olfactory sensitivity and discrimination capacities that can play a substantial role in many aspects of their interaction with conspecifics and the environment. Several studies have demonstrated that olfactory cues may be useful in fruit selection. Here, using a conditioning paradigm, we show that captive spider monkeys (Ateles geoffroyi) display high olfactory discrimination performance between synthetic odor mixtures mimicking ripe and unripe fruits of two wild, primate-consumed, Neotropical plant species. Further, we show that spider monkeys are able to discriminate the odor of ripe fruits from odors that simulate unripe fruits that become increasingly similar to that of ripe ones. These results suggest that the ability of spider monkeys to identify ripe fruits may not depend on the presence of any individual compound that mark fruit ripeness. Further, the results demonstrate that spider monkeys are able to identify ripe fruits even when the odor signal is accompanied by a substantial degree of noise.
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26
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Laska M. Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice. Chem Senses 2015; 40:489-96. [DOI: 10.1093/chemse/bjv032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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27
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Bell IR, Schwartz GE. Enhancement of adaptive biological effects by nanotechnology preparation methods in homeopathic medicines. HOMEOPATHY 2015; 104:123-38. [DOI: 10.1016/j.homp.2014.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 11/16/2014] [Indexed: 01/19/2023]
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28
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Nilsson S, Sjöberg J, Amundin M, Hartmann C, Buettner A, Laska M. Behavioral responses to mammalian blood odor and a blood odor component in four species of large carnivores. PLoS One 2014; 9:e112694. [PMID: 25383706 PMCID: PMC4226632 DOI: 10.1371/journal.pone.0112694] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/10/2014] [Indexed: 11/25/2022] Open
Abstract
Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical “metallic, blood-like” odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, when they were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant differences were found in the number of interactions with the wooden logs impregnated with mammalian blood and the blood odor component in any of the four species. Only one of the four species, the South American bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the five sessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can be as efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a “character impact compound” of mammalian blood odor. Further, the results suggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.
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Affiliation(s)
- Sara Nilsson
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Johanna Sjöberg
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | | | - Constanze Hartmann
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andrea Buettner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Laska
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
- * E-mail:
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29
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Laska M. Olfactory Sensitivity and Odor Structure-Activity Relationships for Aliphatic Ketones in CD-1 Mice. Chem Senses 2014; 39:415-24. [DOI: 10.1093/chemse/bju011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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