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Stark R. The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism. J Neuroendocrinol 2024; 36:e13382. [PMID: 38468186 DOI: 10.1111/jne.13382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 03/13/2024]
Abstract
Olfaction is the most ancient sense and is needed for food-seeking, danger protection, mating and survival. It is often the first sensory modality to perceive changes in the external environment, before sight, taste or sound. Odour molecules activate olfactory sensory neurons that reside on the olfactory epithelium in the nasal cavity, which transmits this odour-specific information to the olfactory bulb (OB), where it is relayed to higher brain regions involved in olfactory perception and behaviour. Besides odour processing, recent studies suggest that the OB extends its function into the regulation of food intake and energy balance. Furthermore, numerous hormone receptors associated with appetite and metabolism are expressed within the OB, suggesting a neuroendocrine role outside the hypothalamus. Olfactory cues are important to promote food preparatory behaviours and consumption, such as enhancing appetite and salivation. In addition, altered metabolism or energy state (fasting, satiety and overnutrition) can change olfactory processing and perception. Similarly, various animal models and human pathologies indicate a strong link between olfactory impairment and metabolic dysfunction. Therefore, understanding the nature of this reciprocal relationship is critical to understand how olfactory or metabolic disorders arise. This present review elaborates on the connection between olfaction, feeding behaviour and metabolism and will shed light on the neuroendocrine role of the OB as an interface between the external and internal environments. Elucidating the specific mechanisms by which olfactory signals are integrated and translated into metabolic responses holds promise for the development of targeted therapeutic strategies and interventions aimed at modulating appetite and promoting metabolic health.
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Affiliation(s)
- Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
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2
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Terral G, Harrell E, Lepousez G, Wards Y, Huang D, Dolique T, Casali G, Nissant A, Lledo PM, Ferreira G, Marsicano G, Roux L. Endogenous cannabinoids in the piriform cortex tune olfactory perception. Nat Commun 2024; 15:1230. [PMID: 38336844 PMCID: PMC10858223 DOI: 10.1038/s41467-024-45161-x] [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: 07/11/2022] [Accepted: 01/17/2024] [Indexed: 02/12/2024] Open
Abstract
Sensory perception depends on interactions between external inputs transduced by peripheral sensory organs and internal network dynamics generated by central neuronal circuits. In the sensory cortex, desynchronized network states associate with high signal-to-noise ratio stimulus-evoked responses and heightened perception. Cannabinoid-type-1-receptors (CB1Rs) - which influence network coordination in the hippocampus - are present in anterior piriform cortex (aPC), a sensory paleocortex supporting olfactory perception. Yet, how CB1Rs shape aPC network activity and affect odor perception is unknown. Using pharmacological manipulations coupled with multi-electrode recordings or fiber photometry in the aPC of freely moving male mice, we show that systemic CB1R blockade as well as local drug infusion increases the amplitude of gamma oscillations in aPC, while simultaneously reducing the occurrence of synchronized population events involving aPC excitatory neurons. In animals exposed to odor sources, blockade of CB1Rs reduces correlation among aPC excitatory units and lowers behavioral olfactory detection thresholds. These results suggest that endogenous endocannabinoid signaling promotes synchronized population events and dampen gamma oscillations in the aPC which results in a reduced sensitivity to external sensory inputs.
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Affiliation(s)
- Geoffrey Terral
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Evan Harrell
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Gabriel Lepousez
- Perception and Memory Unit, CNRS, Joint Research Unit 3571, Université Paris Cité, Institut Pasteur, 75015, Paris, France
| | - Yohan Wards
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Dinghuang Huang
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | | | - Giulio Casali
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Antoine Nissant
- Perception and Memory Unit, CNRS, Joint Research Unit 3571, Université Paris Cité, Institut Pasteur, 75015, Paris, France
| | - Pierre-Marie Lledo
- Perception and Memory Unit, CNRS, Joint Research Unit 3571, Université Paris Cité, Institut Pasteur, 75015, Paris, France
| | - Guillaume Ferreira
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeurO, UMR 1286, F-33000, Bordeaux, France
| | - Giovanni Marsicano
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Lisa Roux
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.
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Klein RM, Motomura VN, Debiasi JD, Moreira EG. Gestational paracetamol exposure induces core behaviors of neurodevelopmental disorders in infant rats and modifies response to a cannabinoid agonist in females. Neurotoxicol Teratol 2023; 99:107279. [PMID: 37391024 DOI: 10.1016/j.ntt.2023.107279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/23/2023] [Accepted: 06/20/2023] [Indexed: 07/02/2023]
Abstract
Paracetamol (PAR) is an over-the-counter analgesic/antipyretic used during pregnancy worldwide. Epidemiological studies have been associating gestational PAR exposure with neurobehavioral alterations in the progeny resembling autism spectrum disorders and attention-deficit hyperactivity disorder symptoms. The endocannabinoid (eCB) dysfunction was previously hypothesized as one of the modes of action by which PAR may harm the developing nervous system. We aimed to evaluate possible effects of gestational exposure to PAR on male and female rat's offspring behavior and if an acute injection of WIN 55,212-2 (WIN, 0.3 mg/kg), a non-specific cannabinoid agonist, prior to behavioral tests, would induce different effects in PAR exposed and non-exposed animals. Pregnant Wistar rats were gavaged with PAR (350 mg/kg/day) or water from gestational day 6 until delivery. Nest-seeking, open field, apomorphine-induced stereotypy, marble burying and three-chamber tests were conducted in 10-, 24-, 25- or 30-days-old rats, respectively. PAR exposure resulted in increased apomorphine-induced stereotyped behavior and time spent in the central area of the open field in exposed female pups. Additionally, it induced hyperactivity in the open field and increased marble burying behavior in both male and female pups. WIN injection modified the behavioral response only in the nest seeking test, and opposite effects were observed in control and PAR-exposed neonate females. Reported alterations are relevant for the neurodevelopmental disorders that have been associated with maternal PAR exposure and suggest that eCB dysfunction may play a role in the action by which PAR may harm the developing brain.
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Affiliation(s)
- Rodrigo Moreno Klein
- Graduation Program in Health Sciences, State University of Londrina, Londrina, PR 86047-610, Brazil
| | | | - Juliana Diosti Debiasi
- Department of Physiological Sciences, State University of Londrina, Londrina, PR 86047-610, Brazil
| | - Estefânia Gastaldello Moreira
- Graduation Program in Health Sciences, State University of Londrina, Londrina, PR 86047-610, Brazil; Department of Physiological Sciences, State University of Londrina, Londrina, PR 86047-610, Brazil.
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Illicit Drug Use and Smell and Taste Dysfunction: A National Health and Nutrition Examination Survey 2013–2014. Healthcare (Basel) 2022; 10:healthcare10050909. [PMID: 35628047 PMCID: PMC9140567 DOI: 10.3390/healthcare10050909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 11/27/2022] Open
Abstract
Taste and smell dysfunction are suspected to be associated with substance use. However, representative epidemiological studies remain insufficient. This cross-sectional study explored the relationship between drug use (including cannabis or hashish, cocaine, heroin, and methamphetamine) and olfactory/gustatory dysfunction using data from the 2013–2014 National Health and Nutrition Examination Survey. In this study, participants who completed the smell examination with mean age of 59 were classified into four groups: cannabis users (n = 845), participants without cannabis use (n = 794), illicit drug users (n = 450), and participants without illicit drug use (n = 2000). Participants who completed the taste examination with mean age of 58 were also categorised into four groups: cannabis users (n = 810), participants without cannabis use (n = 714), illicit drug users (n = 428), and participants without illicit drug use (n = 1815). Logistic regression models investigated the association between cannabis or illicit drug use and smell or taste dysfunctions among study participants. Odds ratios and 95% confidence intervals were calculated. Finally, we did not find correlations between illicit drug use and dysfunction of taste or smell senses; our findings were consistent in many subgroup analyses. We recommend that further studies explore the mechanism and dose of illicit drug use that could have chemosensory impacts.
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Heinbockel T, Straiker A. Cannabinoids Regulate Sensory Processing in Early Olfactory and Visual Neural Circuits. Front Neural Circuits 2021; 15:662349. [PMID: 34305536 PMCID: PMC8294086 DOI: 10.3389/fncir.2021.662349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/11/2021] [Indexed: 12/25/2022] Open
Abstract
Our sensory systems such as the olfactory and visual systems are the target of neuromodulatory regulation. This neuromodulation starts at the level of sensory receptors and extends into cortical processing. A relatively new group of neuromodulators includes cannabinoids. These form a group of chemical substances that are found in the cannabis plant. Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main cannabinoids. THC acts in the brain and nervous system like the chemical substances that our body produces, the endogenous cannabinoids or endocannabinoids, also nicknamed the brain's own cannabis. While the function of the endocannabinoid system is understood fairly well in limbic structures such as the hippocampus and the amygdala, this signaling system is less well understood in the olfactory pathway and the visual system. Here, we describe and compare endocannabinoids as signaling molecules in the early processing centers of the olfactory and visual system, the olfactory bulb, and the retina, and the relevance of the endocannabinoid system for synaptic plasticity.
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Affiliation(s)
- Thomas Heinbockel
- Department of Anatomy, Howard University College of Medicine, Washington, DC, United States
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
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Bryche B, Baly C, Meunier N. Modulation of olfactory signal detection in the olfactory epithelium: focus on the internal and external environment, and the emerging role of the immune system. Cell Tissue Res 2021; 384:589-605. [PMID: 33961125 PMCID: PMC8102665 DOI: 10.1007/s00441-021-03467-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/26/2021] [Indexed: 12/18/2022]
Abstract
Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing environment. Part of these adaptations includes changes of odorant detection by olfactory sensory neurons localized in the olfactory epithelium. It is now well established that internal signals such as hormones, neurotransmitters, or paracrine signals directly affect the electric activity of olfactory neurons. Furthermore, recent data have shown that activity-dependent survival of olfactory neurons is important in the olfactory epithelium. Finally, as olfactory neurons are directly exposed to environmental toxicants and pathogens, the olfactory epithelium also interacts closely with the immune system leading to neuroimmune modulations. Here, we review how detection of odorants can be modulated in the vertebrate olfactory epithelium. We choose to focus on three cellular types of the olfactory epithelium (the olfactory sensory neuron, the sustentacular and microvillar cells) to present the diversity of modulation of the detection of odorant in the olfactory epithelium. We also present some of the growing literature on the importance of immune cells in the functioning of the olfactory epithelium, although their impact on odorant detection is only just beginning to be unravelled.
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Affiliation(s)
- Bertrand Bryche
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France
| | - Christine Baly
- Université Paris Saclay, INRAE, UVSQ, BREED, 78350, Jouy-en-Josas, France
| | - Nicolas Meunier
- Université Paris-Saclay, INRAE, UVSQ, 78350, Jouy-en-Josas, VIM, France.
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Orihuel J, Gómez-Rubio L, Valverde C, Capellán R, Roura-Martínez D, Ucha M, Ambrosio E, Higuera-Matas A. Cocaine-induced Fos expression in the rat brain: Modulation by prior Δ 9-tetrahydrocannabinol exposure during adolescence and sex-specific effects. Brain Res 2021; 1764:147480. [PMID: 33861997 DOI: 10.1016/j.brainres.2021.147480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/24/2021] [Accepted: 04/10/2021] [Indexed: 12/11/2022]
Abstract
It has been suggested that cannabis consumption during adolescence may be an initial step to cocaine use in adulthood. Indeed, previous preclinical data show that adolescent exposure to cannabinoids (both natural and synthetic) potentiates cocaine self-administration in rats. Here we aimed at gaining a deeper understanding of the cellular activation patterns induced by cocaine as revealed by Fos imaging and how these patterns may change due to adolescent exposure to THC. Male and female Wistar rats were administered every other day THC (3 mg/kg i.p.) or vehicle from postnatal day 28-44. At adulthood (PND90) they were given an injection of cocaine (20 mg/kg i.p.) or saline and sacrificed 90 min later. Cocaine-induced Fos activation was measured by immunohistochemistry as an index of cellular activation. We found that cocaine-induced activation in the motor cortex was stronger in THC-exposed rats. Moreover, there was significant sex-dependent interaction between cocaine and adolescent THC exposure in the dorsal hypothalamus, suggesting that cocaine induced a more robust cellular activation in THC-exposed females but not in THC-treated males. Other THC- and cocaine-induced effects were also evident. These results add to the previous literature suggesting that the behavioral, cellular, molecular, and brain-activating actions of cocaine are modulated by early experience with cannabinoids and provide additional knowledge that may explain the enhanced actions of cocaine in rats exposed to cannabinoids during their adolescence.
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Affiliation(s)
- Javier Orihuel
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain; International Graduate School at UNED (Escuela Internacional de Doctorado, UNED), Spain
| | - Laura Gómez-Rubio
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - Claudia Valverde
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - Roberto Capellán
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - David Roura-Martínez
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - Marcos Ucha
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - Emilio Ambrosio
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain
| | - Alejandro Higuera-Matas
- Department of Psychobiology, School of Psychology, National University for Distance Learning (UNED), Madrid, Spain.
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Heinbockel T, Bhatia-Dey N, Shields VDC. Endocannabinoid-mediated neuromodulation in the main olfactory bulb at the interface of environmental stimuli and central neural processing. Eur J Neurosci 2021; 55:1002-1014. [PMID: 33724578 DOI: 10.1111/ejn.15186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 12/16/2022]
Abstract
The olfactory system has become an important functional gateway to understand and analyze neuromodulation since olfactory dysfunction and deficits have emerged as prodromal and, at other times, as first symptoms of many of neurodegenerative, neuropsychiatric and communication disorders. Considering olfactory dysfunction as outcome of altered, damaged and/or inefficient olfactory processing, in the current review, we analyze how olfactory processing interacts with the endocannabinoid signaling system. In the human body, endocannabinoid synthesis is a natural and on-demand response to a wide range of physiological and environmental stimuli. Our current understanding of the response dynamics of the endocannabinoid system is based in large part on research advances in limbic system areas, such as the hippocampus and the amygdala. Functional interactions of this signaling system with olfactory processing and associated pathways are just emerging but appear to grow rapidly with multidimensional approaches. Recent work analyzing the crystal structure of endocannabinoid receptors bound to their agonists in a signaling complex has opened avenues for developing specific therapeutic drugs that could help with neuroinflammation, neurodegeneration, and alleviation/reduction of pain. We discuss the role of endocannabinoids as signaling molecules in the olfactory system and the relevance of the endocannabinoid system for synaptic plasticity.
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Affiliation(s)
- Thomas Heinbockel
- Department of Anatomy, Howard University College of Medicine, Washington, DC, USA
| | - Naina Bhatia-Dey
- Department of Anatomy, Howard University College of Medicine, Washington, DC, USA
| | - Vonnie D C Shields
- Biological Sciences Department, Fisher College of Science and Mathematics, Towson University, Towson, MD, USA
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Mielnik CA, Lam VM, Ross RA. CB 1 allosteric modulators and their therapeutic potential in CNS disorders. Prog Neuropsychopharmacol Biol Psychiatry 2021; 106:110163. [PMID: 33152384 DOI: 10.1016/j.pnpbp.2020.110163] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/30/2020] [Accepted: 10/29/2020] [Indexed: 01/05/2023]
Abstract
CB1 is the most abundant GPCR found in the mammalian brain. It has garnered considerable attention as a potential therapeutic drug target. CB1 is involved in a wide range of physiological and psychiatric processes and has the potential to be targeted in a wide range of disease states. However, most of the selective and non-selective synthetic CB1 agonists and antagonists/inverse agonists developed to date are primarily used as research tools. No novel synthetic cannabinoids are currently in the clinic for use in psychiatric illness; synthetic analogues of the phytocannabinoid THC are on the market to treat nausea and vomiting caused by cancer chemotherapy, along with off-label use for pain. Novel strategies are being explored to target CB1, but with emphasis on the elimination or mitigation of the potential psychiatric adverse effects that are observed by central agonism/antagonism of CB1. New pharmacological options are being pursued that may avoid these adverse effects while preserving the potential therapeutic benefits of CB1 modulation. Allosteric modulation of CB1 is one such approach. In this review, we will summarize and critically analyze both the in vitro characterization and in vivo validation of CB1 allosteric modulators developed to date, with a focus on CNS therapeutic effects.
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Affiliation(s)
- Catharine A Mielnik
- Department of Pharmacology & Toxicology, University of Toronto, ON M5S 1A8, Canada
| | - Vincent M Lam
- Department of Pharmacology & Toxicology, University of Toronto, ON M5S 1A8, Canada
| | - Ruth A Ross
- Department of Pharmacology & Toxicology, University of Toronto, ON M5S 1A8, Canada.
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Soria-Gómez E. Special Issue "Olfaction: From Genes to Behavior". Genes (Basel) 2020; 11:genes11060654. [PMID: 32549403 PMCID: PMC7348778 DOI: 10.3390/genes11060654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/19/2022] Open
Affiliation(s)
- Edgar Soria-Gómez
- Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain; or
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, 48940 Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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