1
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Zhang L, Nagel M, Olson WP, Chesler AT, O'Connor DH. Trigeminal innervation and tactile responses in mouse tongue. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.17.553449. [PMID: 37645855 PMCID: PMC10462066 DOI: 10.1101/2023.08.17.553449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The mammalian tongue is richly innervated with somatosensory, gustatory and motor fibers. These form the basis of many ethologically important functions such as eating, speaking and social grooming. Despite its high tactile acuity and sensitivity, the neural basis of tongue mechanosensation remains largely mysterious. Here we explored the organization of mechanosensory afferents in the tongue and found that each lingual papilla is innervated by Piezo2 + trigeminal neurons. Notably, each fungiform papilla contained highly specialized ring-like sensory neuron terminations that asymmetrically circumscribe the taste buds. Myelinated lingual afferents in the mouse lingual papillae did not form corpuscular sensory end organs but rather had only free nerve endings. In vivo single-unit recordings from the trigeminal ganglion revealed lingual low-threshold mechanoreceptors (LTMRs) with conduction velocities in the Aδ range or above and distinct adaptation properties ranging from intermediately adapting (IA) to rapidly adapting (RA). IA units were sensitive to both static indentation and stroking, while RA units had a preference for tangential forces applied by stroking. Lingual LTMRs were not directly responsive to rapid cooling or chemicals that can induce astringent or numbing sensations. Sparse labeling of lingual afferents in the tongue revealed distinct terminal morphologies and innervation patterns in fungiform and filiform papillae. Together, our results indicate that fungiform papillae are mechanosensory structures, while suggesting a simple model that links the functional and anatomical properties of tactile sensory neurons in the tongue.
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2
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Li J, Zumpano KT, Lemon CH. Separation of Oral Cooling and Warming Requires TRPM8. J Neurosci 2024; 44:e1383232024. [PMID: 38316563 PMCID: PMC10941239 DOI: 10.1523/jneurosci.1383-23.2024] [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: 07/21/2023] [Revised: 01/13/2024] [Accepted: 01/24/2024] [Indexed: 02/07/2024] Open
Abstract
Cooling sensations arise inside the mouth during ingestive and homeostasis behaviors. Oral presence of cooling temperature engages the cold and menthol receptor TRPM8 (transient receptor potential melastatin 8) on trigeminal afferents. Yet, how TRPM8 influences brain and behavioral responses to oral temperature is undefined. Here we used in vivo neurophysiology to record action potentials stimulated by cooling and warming of oral tissues from trigeminal nucleus caudalis neurons in female and male wild-type and TRPM8 gene deficient mice. Using these lines, we also measured orobehavioral licking responses to cool and warm water in a novel, temperature-controlled fluid choice test. Capture of antidromic electrophysiological responses to thalamic stimulation identified that wild-type central trigeminal neurons showed diverse responses to oral cooling. Some neurons displayed relatively strong excitation to cold <10°C (COLD neurons) while others responded to only a segment of mild cool temperatures below 30°C (COOL neurons). Notably, TRPM8 deficient mice retained COLD-type but lacked COOL cells. This deficit impaired population responses to mild cooling temperatures below 30°C and allowed warmth-like (≥35°C) neural activity to pervade the normally innocuous cool temperature range, predicting TRPM8 deficient mice would show anomalously similar orobehavioral responses to warm and cool temperatures. Accordingly, TRPM8 deficient mice avoided both warm (35°C) and mild cool (≤30°C) water and sought colder temperatures in fluid licking tests, whereas control mice avoided warm but were indifferent to mild cool and colder water. Results imply TRPM8 input separates cool from warm temperature sensing and suggest other thermoreceptors also participate in oral cooling sensation.
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Affiliation(s)
- Jinrong Li
- School of Biological Sciences, University of Oklahoma, Norman, OK 73019
| | - Kyle T Zumpano
- School of Biological Sciences, University of Oklahoma, Norman, OK 73019
| | - Christian H Lemon
- School of Biological Sciences, University of Oklahoma, Norman, OK 73019
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3
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Sato H, Satoh K, Nozaki K, Yugawa M, Kato T, Toyoda H, Katagiri A, Suda N, Adachi K. Reduced menthol sensitivity in a prodromal Parkinson's disease model induced by intranasal rotenone treatment. Front Cell Neurosci 2024; 18:1345651. [PMID: 38380382 PMCID: PMC10876781 DOI: 10.3389/fncel.2024.1345651] [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: 11/28/2023] [Accepted: 01/19/2024] [Indexed: 02/22/2024] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms, and it is associated with several prodromal non-motor symptoms, including an impaired sense of smell, taste and touch. We previously reported that bitter taste impairments occur independently of olfactory impairments in an early-stage PD animal model using short-term intranasal rotenone-treated mice. Cool temperatures also affect bitter taste perception, but it remains unclear whether or not bitter taste impairments result from an altered sensitivity for intraoral cool stimuli. We examined disturbances in the intraoral menthol sensitivity, such as coolness at low concentrations of menthol, using a brief-access test. Once a day, one solution from the 7-concentration series of (-)-menthol (0-2.3 mM) or the bitter taste quinine-HCl (0.3 mM) was randomly presented 20 times for 10 s to water-deprived mice before and 1 week after rotenone treatment. The total number of licks within 20 times was significantly decreased with the presentation of 2.3 mM menthol and quinine-HCl, compared to distilled water in untreated mice, but not in rotenone-treated mice. The correlation between the licks for quinine-HCl and that for menthol was increased after rotenone treatment. In contrast, the 2-bottle choice test for 48 h clarified that menthol sensitivity was increased after rotenone treatment. Furthermore, a thermal place preference test revealed that seeking behavior toward a cold-floored room was increased in the rotenone-treated mice despite the unchanged plantar cutaneous cold sensitivity. These results suggest that taste impairments in this model mice are at least partly due to intraoral somatosensory impairments, accompanied by peripheral/central malfunction.
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Affiliation(s)
- Hajime Sato
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
| | - Keitaro Satoh
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
| | - Kazunori Nozaki
- Division of Medical Information, Osaka University Dental Hospital, Suita, Japan
| | - Misato Yugawa
- Division of Orthodontics, Meikai University School of Dentistry, Sakado, Japan
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Hiroki Toyoda
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Ayano Katagiri
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Naoto Suda
- Division of Orthodontics, Meikai University School of Dentistry, Sakado, Japan
| | - Kazunori Adachi
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
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4
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Kuramoto E, Fukushima M, Sendo R, Ohno S, Iwai H, Yamanaka A, Sugimura M, Goto T. Three-dimensional topography of rat trigeminal ganglion neurons using a combination of retrograde labeling and tissue-clearing techniques. J Comp Neurol 2024; 532:e25584. [PMID: 38341648 DOI: 10.1002/cne.25584] [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: 09/07/2023] [Revised: 12/28/2023] [Accepted: 01/09/2024] [Indexed: 02/12/2024]
Abstract
The trigeminal nerve is the sensory afferent of the orofacial regions and divided into three major branches. Cell bodies of the trigeminal nerve lie in the trigeminal ganglion and are surrounded by satellite cells. There is a close interaction between ganglion cells via satellite cells, but the function is not fully understood. In the present study, we clarified the ganglion cells' three-dimensional (3D) localization, which is essential to understand the functions of cell-cell interactions in the trigeminal ganglion. Fast blue was injected into 12 sites of the rat orofacial regions, and ganglion cells were retrogradely labeled. The labeled trigeminal ganglia were cleared by modified 3DISCO, imaged with confocal laser-scanning microscopy, and reconstructed in 3D. Histograms of the major axes of the fast blue-positive somata revealed that the peak major axes of the cells innervating the skin/mucosa were smaller than those of cells innervating the deep structures. Ganglion cells innervating the ophthalmic, maxillary, and mandibular divisions were distributed in the anterodorsal, central, and posterolateral portions of the trigeminal ganglion, respectively, with considerable overlap in the border region. The intermingling in the distribution of ganglion cells within each division was also high, in particular, within the mandibular division. Specifically, intermingling was observed in combinations of tongue and masseter/temporal muscles, maxillary/mandibular molars and masseter/temporal muscles, and tongue and mandibular molars. Double retrograde labeling confirmed that some ganglion cells innervating these combinations were closely apposed. Our data provide essential information for understanding the function of ganglion cell-cell interactions via satellite cells.
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Grants
- JP23H03119 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP23K09316 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP19K10058 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP19K10336 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP19KK0419 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H05162 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22K09916 Grants-in-Aid from The Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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Affiliation(s)
- Eriko Kuramoto
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Makoto Fukushima
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ryozo Sendo
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
- Department of Dental Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Sachi Ohno
- Department of Dental Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Haruki Iwai
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Atsushi Yamanaka
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Mitsutaka Sugimura
- Department of Dental Anesthesiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tetsuya Goto
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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Bouaichi CG, Odegaard KE, Neese C, Vincis R. Intraoral thermal processing in the gustatory cortex of awake mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.526681. [PMID: 36798208 PMCID: PMC9934522 DOI: 10.1101/2023.02.06.526681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Oral temperature is a sensory cue relevant to food preference and nutrition. To understand how orally-sourced thermal inputs are represented in the gustatory cortex (GC) we recorded neural responses from the GC of male and female mice presented with deionized water at different innocuous temperatures (14 °C, 25 °C, 36 °C) and taste stimuli (room temperature). Our results demonstrate that GC neurons encode orally-sourced thermal information in the absence of classical taste qualities at the single neuron and population levels, as confirmed through additional experiments comparing GC neuron responses to water and artificial saliva. Analysis of thermal-evoked responses showed broadly tuned neurons that responded to temperature in a mostly monotonic manner. Spatial location may play a minor role regarding thermosensory activity; aside from the most ventral GC, neurons reliably responded to and encoded thermal information across the dorso-ventral and antero-postero cortical axes. Additional analysis revealed that more than half of GC neurons that encoded chemosensory taste stimuli also accurately discriminated thermal information, providing additional evidence of the GC's involvement in processing thermosensory information important for ingestive behaviors. In terms of convergence, we found that GC neurons encoding information about both taste and temperature were broadly tuned and carried more information than taste-selective only neurons; both groups encoded similar information about the palatability of stimuli. Altogether, our data reveal new details of the cortical code for the mammalian intraoral thermosensory system in behaving mice and pave the way for future investigations on GC functions and operational principles with respect to thermogustation.
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Affiliation(s)
- Cecilia G Bouaichi
- Florida State University, Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics
| | - Katherine E Odegaard
- Florida State University, Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics
| | - Camden Neese
- Florida State University, Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics
| | - Roberto Vincis
- Florida State University, Department of Biological Science and Programs in Neuroscience, Molecular Biophysics and Cell and Molecular Biology
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6
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He W, Liang L, Zhang Y. Pungency Perception and the Interaction with Basic Taste Sensations: An Overview. Foods 2023; 12:2317. [PMID: 37372528 DOI: 10.3390/foods12122317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/17/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The perception of pungency can be attributed to the combination of pain and heat, and it has critical impacts on food flavor and food consumption preferences. Many studies have reported a variety of pungent ingredients with different Scoville heat units (SHU), and the mechanism of pungent perception was revealed in vivo and in vitro. The worldwide use of spices containing pungent ingredients has led to an increasing awareness of their effects on basic tastes. However, the interaction between basic tastes and pungency perception based on structure-activity relationship, taste perception mechanism and neurotransmission lacks review and summary, considering its brighter prospects in food flavor. Thus, in this review, common pungency substances and pungency evaluation methods, and the mechanism of pungency perception is presented, and the interaction between basic tastes and pungency perception and the possible factors of their interaction are reviewed in detail. Pungent stimuli are mainly transduced through transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential fixed hormone isoform (TRPA1) activated by stimulants. Using modern detection techniques combined with sensory standards, different substances produce different degrees of pungent stimulation, ranging from 104 to 107 SHU/g. Pungent stimuli can affect taste receptor or channel protein conformation and regulate taste bud cell sensitivity by producing neurotransmission products. The products of neurotransmission and taste receptor cell activation in turn act on taste perception. When there are simultaneous effects of taste perception, pungency stimulation may enhance the perception of salty at a certain concentration, with a mutual inhibition effect with sour, sweet, and bitter taste, while its interaction with umami taste is not obvious. However, due to the complexity of perception and the uncertainty of many perceptual receptors or channels, the current studies of interactions are still controversial. Based on the understanding of the mechanism and influencing factors, the availability of pungency substances is proposed in the perspective of food industry in order to achieve new development.
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Affiliation(s)
- Wei He
- Food Laboratory of Zhongyuan, Beijing Technology and Business University, Beijing 100048, China
- Key Laboratory of Flavor Science of China General Chamber of Commerce, Beijing Technology and Business University, Beijing 100048, China
| | - Li Liang
- Food Laboratory of Zhongyuan, Beijing Technology and Business University, Beijing 100048, China
- Key Laboratory of Flavor Science of China General Chamber of Commerce, Beijing Technology and Business University, Beijing 100048, China
| | - Yuyu Zhang
- Food Laboratory of Zhongyuan, Beijing Technology and Business University, Beijing 100048, China
- Key Laboratory of Flavor Science of China General Chamber of Commerce, Beijing Technology and Business University, Beijing 100048, China
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7
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Zhu Y, Thaploo D, Han P, Hummel T. Processing of Sweet, Astringent and Pungent Oral Stimuli in the Human Brain. Neuroscience 2023; 520:144-155. [PMID: 36966878 DOI: 10.1016/j.neuroscience.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/20/2023] [Accepted: 03/11/2023] [Indexed: 04/03/2023]
Abstract
Taste and oral somatosensation are intimately related to each other from peripheral receptors to the central nervous system. Oral astringent sensation is thought to contain both gustatory and somatosensory components. In the present study, we compared the cerebral response to an astringent stimulus (tannin), with the response to one typical taste stimulus (sweet - sucrose) and one typical somatosensory stimulus (pungent - capsaicin) using functional magnetic resonance imaging (fMRI) of 24 healthy subjects. Three distributed brain sub-regions responded significantly different to the three types of oral stimulations: lobule IX of the cerebellar hemisphere, right dorsolateral superior frontal gyrus, and left middle temporal gyrus. This suggests that these regions play a major role in the discrimination of astringency, taste, and pungency.
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Affiliation(s)
- Yunmeng Zhu
- Smell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| | - Divesh Thaploo
- Smell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| | - Pengfei Han
- Faculty of Psychology, Southwest University, Chongqing, China.
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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8
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Moayedi Y, Xu S, Obayashi SK, Hoffman BU, Gerling GJ, Lumpkin EA. The cellular basis of mechanosensation in mammalian tongue. Cell Rep 2023; 42:112087. [PMID: 36763499 PMCID: PMC10409885 DOI: 10.1016/j.celrep.2023.112087] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 11/16/2022] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Mechanosensory neurons that innervate the tongue provide essential information to guide feeding, speech, and social grooming. We use in vivo calcium imaging of mouse trigeminal ganglion neurons to identify functional groups of mechanosensory neurons innervating the anterior tongue. These sensory neurons respond to thermal and mechanical stimulation. Analysis of neuronal activity patterns reveal that most mechanosensory trigeminal neurons are tuned to detect moving stimuli across the tongue. Using an unbiased, multilayer hierarchical clustering approach to classify pressure-evoked activity based on temporal response dynamics, we identify five functional classes of mechanosensory neurons with distinct force-response relations and adaptation profiles. These populations are tuned to detect different features of touch. Molecular markers of functionally distinct clusters are identified by analyzing cluster representation in genetically marked neuronal subsets. Collectively, these studies provide a platform for defining the contributions of functionally distinct mechanosensory neurons to oral behaviors crucial for survival in mammals.
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Affiliation(s)
- Yalda Moayedi
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA; Department of Otolaryngology - Head & Neck Surgery, Columbia University, New York, NY 10032, USA
| | - Shan Xu
- School of Engineering and Applied Science, University of Virginia, Charlottesville, VA 22904, USA
| | - Sophie K Obayashi
- Department of Molecular & Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Benjamin U Hoffman
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Gregory J Gerling
- School of Engineering and Applied Science, University of Virginia, Charlottesville, VA 22904, USA.
| | - Ellen A Lumpkin
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Molecular & Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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9
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Shannonhouse J, Gomez R, Son H, Zhang Y, Kim YS. In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia. J Vis Exp 2023:10.3791/64826. [PMID: 36847407 PMCID: PMC10785773 DOI: 10.3791/64826] [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] [Indexed: 02/12/2023] Open
Abstract
Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the cytoplasm or the release of intracellular Ca2+ stores. Pirt-GCaMP3-based Ca2+ imaging of primary sensory neurons of the dorsal root ganglion (DRG) in mice offers the advantage of simultaneous measurement of a large number of cells. Up to 1,800 neurons can be monitored, allowing neuronal networks and somatosensory processes to be studied as an ensemble in their normal physiological context at a populational level in vivo. The large number of neurons monitored allows the detection of activity patterns that would be challenging to detect using other methods. Stimuli can be applied to the mouse hindpaw, allowing the direct effects of stimuli on the DRG neuron ensemble to be studied. The number of neurons producing Ca2+ transients as well as the amplitude of Ca2+ transients indicates sensitivity to specific sensory modalities. The diameter of neurons provides evidence of activated fiber types (non-noxious mechano vs. noxious pain fibers, Aβ, Aδ, and C fibers). Neurons expressing specific receptors can be genetically labeled with td-Tomato and specific Cre recombinases together with Pirt-GCaMP. Therefore, Pirt-GCaMP3 Ca2+ imaging of DRG provides a powerful tool and model for the analysis of specific sensory modalities and neuron subtypes acting as an ensemble at the populational level to study pain, itch, touch, and other somatosensory signals.
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Affiliation(s)
- John Shannonhouse
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Ruben Gomez
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Hyeonwi Son
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Yan Zhang
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio
| | - Yu Shin Kim
- Department of Oral & Maxillofacial Surgery, School of Dentistry, University of Texas Health Science Center at San Antonio; Programs in Integrated Biomedical Sciences, Translational Sciences, Biomedical Engineering, Radiological Sciences, University of Texas Health Science Center at San Antonio;
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10
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Tatsumi M, Kishi T, Ishida S, Kawana H, Uwamizu A, Ono Y, Kawakami K, Aoki J, Inoue A. Ectodomain shedding of EGFR ligands serves as an activation readout for TRP channels. PLoS One 2023; 18:e0280448. [PMID: 36668668 PMCID: PMC9858409 DOI: 10.1371/journal.pone.0280448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/29/2022] [Indexed: 01/21/2023] Open
Abstract
Transient receptor potential (TRP) channels are activated by various extracellular and intracellular stimuli and are involved in many physiological events. Because compounds that act on TRP channels are potential candidates for therapeutic agents, a simple method for evaluating TRP channel activation is needed. In this study, we demonstrated that a transforming growth factor alpha (TGFα) shedding assay, previously developed for detecting G-protein-coupled receptor (GPCR) activation, can also detect TRP channel activation. This assay is a low-cost, easily accessible method that requires only an absorbance microplate reader. Mechanistically, TRP-channel-triggered TGFα shedding is achieved by both of a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and 17 (ADAM17), whereas the GPCR-induced TGFα shedding response depends solely on ADAM17. This difference may be the result of qualitative or quantitative differences in intracellular Ca2+ kinetics between TRP channels and GPCRs. Use of epidermal growth factor (EGF) and betacellulin (BTC), substrates of ADAM10, improved the specificity of the shedding assay by reducing background responses mediated by endogenously expressed GPCRs. This assay for TRP channel measurement will not only facilitate the high-throughput screening of TRP channel ligands but also contribute to understanding the roles played by TRP channels as regulators of membrane protein ectodomain shedding.
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Affiliation(s)
- Manae Tatsumi
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Takayuki Kishi
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Satoru Ishida
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Hiroki Kawana
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Akiharu Uwamizu
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yuki Ono
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kouki Kawakami
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Asuka Inoue
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
- * E-mail:
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11
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Bouaichi CG, Odegaard KE, Neese C, Vincis R. Oral thermal processing in the gustatory cortex of awake mice. Chem Senses 2023; 48:bjad042. [PMID: 37850853 PMCID: PMC10630187 DOI: 10.1093/chemse/bjad042] [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: 07/27/2023] [Indexed: 10/19/2023] Open
Abstract
Oral temperature is a sensory cue relevant to food preference and nutrition. To understand how orally sourced thermal inputs are represented in the gustatory cortex (GC), we recorded neural responses from the GC of male and female mice presented with deionized water at different innocuous temperatures (14 °C, 25 °C, and 36 °C) and taste stimuli (room temperature). Our results demonstrate that GC neurons encode orally sourced thermal information in the absence of classical taste qualities at the single neuron and population levels, as confirmed through additional experiments comparing GC neuron responses to water and artificial saliva. Analysis of thermal-evoked responses showed broadly tuned neurons that responded to temperature in a mostly monotonic manner. Spatial location may play a minor role regarding thermosensory activity; aside from the most ventral GC, neurons reliably responded to and encoded thermal information across the dorso-ventral and antero-postero cortical axes. Additional analysis revealed that more than half of the GC neurons that encoded chemosensory taste stimuli also accurately discriminated thermal information, providing additional evidence of the GC's involvement in processing thermosensory information important for ingestive behaviors. In terms of convergence, we found that GC neurons encoding information about both taste and temperature were broadly tuned and carried more information than taste-selective-only neurons; both groups encoded similar information about the palatability of stimuli. Altogether, our data reveal new details of the cortical code for the mammalian oral thermosensory system in behaving mice and pave the way for future investigations on GC functions and operational principles with respect to thermogustation.
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Affiliation(s)
- Cecilia G Bouaichi
- Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics, Florida State University, Tallahassee, FL, United States
| | - Katherine E Odegaard
- Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics, Florida State University, Tallahassee, FL, United States
| | - Camden Neese
- Department of Biological Science and Programs in Neuroscience, Cell and Molecular Biology, and Biophysics, Florida State University, Tallahassee, FL, United States
| | - Roberto Vincis
- Department of Biological Science and Programs in Neuroscience, Molecular Biophysics and Cell and Molecular Biology, Florida State University, Tallahassee, FL, United States
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Roriz M, Brito P, Teixeira FJ, Brito J, Teixeira VH. Performance effects of internal pre- and per-cooling across different exercise and environmental conditions: A systematic review. Front Nutr 2022; 9:959516. [PMID: 36337635 PMCID: PMC9632747 DOI: 10.3389/fnut.2022.959516] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/19/2022] [Indexed: 11/13/2022] Open
Abstract
Exercise in a hot and humid environment may endanger athlete's health and affect physical performance. This systematic review aimed to examine whether internal administration of ice, cold beverages or menthol solutions may be beneficial for physical performance when exercising in different environmental conditions and sports backgrounds. A systematic search was performed in PubMed, Web of Science, Scopus and SPORTDiscus databases, from inception to April 2022, to identify studies meeting the following inclusion criteria: healthy male and female physically active individuals or athletes (aged ≥18 years); an intervention consisting in the internal administration (i.e., ingestion or mouth rinse) of ice slush, ice slurry or crushed ice and/or cold beverages and/or menthol solutions before and/or during exercise; a randomized crossover design with a control or placebo condition; the report of at least one physical performance outcome; and to be written in English. Our search retrieved 2,714 articles in total; after selection, 43 studies were considered, including 472 participants, 408 men and 64 women, aged 18-42 years, with a VO2max ranging from 46.2 to 67.2 mL⋅kg-1⋅min-1. Average ambient temperature and relative humidity during the exercise tasks were 32.4 ± 3.5°C (ranging from 22°C to 38°C) and 50.8 ± 13.4% (varying from 20.0% to 80.0%), respectively. Across the 43 studies, 7 exclusively included a menthol solution mouth rinse, 30 exclusively involved ice slurry/ice slush/crushed ice/cold beverages intake, and 6 examined both the effect of thermal and non-thermal internal techniques in the same protocol. Rinsing a menthol solution (0.01%) improved physical performance during continuous endurance exercise in the heat. Conversely, the ingestion of ice or cold beverages did not seem to consistently increase performance, being more likely to improve performance in continuous endurance trials, especially when consumed during exercises. Co-administration of menthol with or within ice beverages seems to exert a synergistic effect by improving physical performance. Even in environmental conditions that are not extreme, internal cooling strategies may have an ergogenic effect. Further studies exploring both intermittent and outdoor exercise protocols, involving elite male and female athletes and performed under not extreme environmental conditions are warranted. Systematic review registration: [https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021268197], identifier [CRD42021268197].
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Affiliation(s)
- Maria Roriz
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), Porto, Portugal
- Futebol Clube do Porto, Porto, Portugal
| | - Pedro Brito
- Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Maia, ISMAI, Maia, Portugal
| | - Filipe J. Teixeira
- Interdisciplinary Center for the Study of Human Performance (CIPER), Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz-Quebrada, Portugal
- Atlântica, Instituto Universitário, Fábrica da Pólvora de Barcarena, Barcarena, Portugal
- Bettery Lifelab, Bettery S.A., Lisbon, Portugal
| | - João Brito
- Portugal Football School, Portuguese Football Federation, Oeiras, Portugal
| | - Vitor Hugo Teixeira
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), Porto, Portugal
- Futebol Clube do Porto, Porto, Portugal
- Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
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13
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Zhao H, Ren S, Yang H, Tang S, Guo C, Liu M, Tao Q, Ming T, Xu H. Peppermint essential oil: its phytochemistry, biological activity, pharmacological effect and application. Biomed Pharmacother 2022; 154:113559. [PMID: 35994817 DOI: 10.1016/j.biopha.2022.113559] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/11/2022] [Accepted: 08/14/2022] [Indexed: 12/18/2022] Open
Abstract
Mentha (also known as peppermint), a genus of plants in the taxonomic family Lamiaceae (mint family), is widely distributed throughout temperate regions of the world. Mentha contains various constituents that are classified as peppermint essential oil (PEO) and non-essential components. PEO, consisting mainly of menthol, menthone, neomenthol and iso-menthone, is a mixture of volatile metabolites with anti-inflammatory, antibacterial, antiviral, scolicidal, immunomodulatory, antitumor, neuroprotective, antifatigue and antioxidant activities. Mounting evidence indicates that PEO may pharmacologically protect gastrointestinal, liver, kidney, skin, respiratory, brain and nervous systems, and exert hypoglycemic and hypolipidemic effects. Clinically, PEO is used for gastrointestinal and dermatological diseases, postoperative adjuvant therapy and other fields. This review aims to address the advances in the extraction and isolation of PEO, its biological activities, pharmacological effects, toxicity and applications, with an emphasis on the efficacy of PEO on burn wounds and psoriasis, providing a comprehensive foundation for research, development and application of PEO in future.
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Affiliation(s)
- Hui Zhao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; Department of Pharmacology, School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450000, China
| | - Shan Ren
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Han Yang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Shun Tang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Chenyang Guo
- Department of Pharmacology, School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450000, China
| | - Maolun Liu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Qiu Tao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Tianqi Ming
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Haibo Xu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
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Hu M, Doyle AD, Yamada KM, Kulkarni AB. Visualization of trigeminal ganglion sensory neuronal signaling regulated by Cdk5. Cell Rep 2022; 38:110458. [PMID: 35263573 PMCID: PMC9004325 DOI: 10.1016/j.celrep.2022.110458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 11/24/2021] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
The mechanisms underlying facial pain are still incompletely understood, posing major therapeutic challenges. Cyclin-dependent kinase 5 (Cdk5) is a key neuronal kinase involved in pain signaling. However, the regulatory roles of Cdk5 in facial pain signaling and the possibility of therapeutic intervention at the level of mouse trigeminal ganglion primary neurons remain elusive. In this study, we use optimized intravital imaging to directly compare trigeminal neuronal activities after mechanical, thermal, and chemical stimulation. We then test whether facial inflammatory pain in mice could be alleviated by the Cdk5 inhibitor peptide TFP5. We demonstrate regulation of total Ca2+ intensity by Cdk5 activity using transgenic and knockout mouse models. In mice with vibrissal pad inflammation, application of TFP5 specifically decreases total Ca2+ intensity in response to noxious stimuli. It also alleviates inflammation-induced allodynia by inhibiting activation of trigeminal peripheral sensory neurons. Cdk5 inhibitors may provide promising non-opioid candidates for pain treatment.
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Affiliation(s)
- Minghan Hu
- Functional Genomics Section and Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Andrew D Doyle
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Kenneth M Yamada
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
| | - Ashok B Kulkarni
- Functional Genomics Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Drive, MSC 4359, Bethesda, MD, USA.
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Ishida H, Zhang Y, Gomez R, Shannonhouse J, Son H, Banik R, Kim YS. In Vivo Calcium Imaging Visualizes Incision-Induced Primary Afferent Sensitization and Its Amelioration by Capsaicin Pretreatment. J Neurosci 2021; 41:8494-8507. [PMID: 34452938 PMCID: PMC8513701 DOI: 10.1523/jneurosci.0457-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023] Open
Abstract
Previous studies have shown that infiltration of capsaicin into the surgical site can prevent incision-induced spontaneous pain like behaviors and heat hyperalgesia. In the present study, we aimed to monitor primary sensory neuron Ca2+ activity in the intact dorsal root ganglia (DRG) using Pirt-GCaMP3 male and female mice pretreated with capsaicin or vehicle before the plantar incision. Intraplantar injection of capsaicin (0.05%) significantly attenuated spontaneous pain, mechanical, and heat hypersensitivity after plantar incision. The Ca2+ response in in vivo DRG and in in situ spinal cord was significantly enhanced in the ipsilateral side compared with contralateral side or naive control. Primary sensory nerve fiber length was significantly decreased in the incision skin area in capsaicin-pretreated animals detected by immunohistochemistry and placental alkaline phosphatase (PLAP) staining. Thus, capsaicin pretreatment attenuates incisional pain by suppressing Ca2+ response because of degeneration of primary sensory nerve fibers in the skin.SIGNIFICANCE STATEMENT Postoperative surgery pain is a major health and economic problem worldwide with ∼235 million major surgical procedures annually. Approximately 50% of these patients report uncontrolled or poorly controlled postoperative pain. However, mechanistic studies of postoperative surgery pain in primary sensory neurons have been limited to in vitro models or small numbers of neurons. Using an innovative, distinctive, and interdisciplinary in vivo populational dorsal root ganglia (DRG) imaging (>1800 neurons/DRG) approach, we revealed increased DRG neuronal Ca2+ activity from postoperative pain mouse model. This indicates widespread DRG primary sensory neuron plasticity. Increased neuronal Ca2+ activity occurs among various sizes of neurons but mostly in small-diameter and medium-diameter nociceptors. Capsaicin pretreatment as a therapeutic option significantly attenuates Ca2+ activity and postoperative pain.
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Affiliation(s)
- Hirotake Ishida
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
| | - Yan Zhang
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
| | - Ruben Gomez
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
| | - John Shannonhouse
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
| | - Hyeonwi Son
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
| | - Ratan Banik
- Department of Anesthesiology, School of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455
| | - Yu Shin Kim
- Department of Oral and Maxillofacial Surgery, University of Texas Health and Science Center at San Antonio, Texas, 78229
- Programs in Integrated Biomedical Sciences, Translational Sciences, Biomedical Engineering, Radiological Sciences, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
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Quantitative but not qualitative flavor recognition impairments in COVID-19 patients. Ir J Med Sci 2021; 191:1759-1766. [PMID: 34562193 PMCID: PMC8475319 DOI: 10.1007/s11845-021-02786-x] [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: 07/19/2021] [Accepted: 09/12/2021] [Indexed: 11/24/2022]
Abstract
Background Smell and taste dysfunctions (STDs) are symptoms associated with COVID-19 syndrome, even if their incidence is still uncertain and variable. Aims In this study, the effects of SARS-CoV-2 infection on chemosensory function have been investigated using both a self-reporting questionnaire on smell and flavor perception, and a simplified flavor test. Methods A total of 111 subjects (19 hospitalized [HOS] and 37 home-isolated [HI] COVID-19 patients, and 55 healthy controls [CTRL]) were enrolled in the study. They received a self-evaluation questionnaire and a self-administered flavor test kit. The flavor test used consists in the self-administration of four solutions with a pure olfactory stimulus (coffee), a mixed olfactory-trigeminal stimulus (peppermint), and a complex chemical mixture (banana). Results After SARS-CoV-2 infection, HOS and HI patients reported similar prevalence of STDs, with a significant reduction of both smell and flavor self-estimated perception. The aromas of the flavor test were recognized by HI and HOS COVID-19 patients similarly to CTRL; however, the intensity of the perceived aromas was significantly lower in patients compared to controls. Conclusion Data reported here suggests that a chemosensory impairment is present after SARS-CoV-2 infection, and the modified “flavor test” could be a novel self-administering objective screening test to assess STDs in COVID-19 patients. Clinical trial registration no. NCT04840966; April 12, 2021, retrospectively registered Supplementary Information The online version contains supplementary material available at 10.1007/s11845-021-02786-x.
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Gutierrez R, Simon SA. Physiology of Taste Processing in the Tongue, Gut, and Brain. Compr Physiol 2021; 11:2489-2523. [PMID: 34558667 DOI: 10.1002/cphy.c210002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The gustatory system detects and informs us about the nature of various chemicals we put in our mouth. Some of these have nutritive value (sugars, amino acids, salts, and fats) and are appetitive and avidly ingested, whereas others (atropine, quinine, nicotine) are aversive and rapidly rejected. However, the gustatory system is mainly responsible for evoking the perception of a limited number of qualities that humans taste as sweet, umami, bitter, sour, salty, and perhaps fat [free fatty acids (FFA)] and starch (malto-oligosaccharides). The complex flavors and mouthfeel that we experience while eating food result from the integration of taste, odor, texture, pungency, and temperature. The latter three arise primarily from the somatosensory (trigeminal) system. The sensory organs used for detecting and transducing many chemicals are found in taste buds (TBs) located throughout the tongue, soft palate esophagus, and epiglottis. In parallel with the taste system, the trigeminal nerve innervates the peri-gemmal epithelium to transmit temperature, mechanical stimuli, and painful or cooling sensations such as those produced by changes in temperature as well as from chemicals like capsaicin and menthol, respectively. This article gives an overview of the current knowledge about these TB cells' anatomy and physiology and their trigeminal induced sensations. We then discuss how taste is represented across gustatory cortices using an intermingled and spatially distributed population code. Finally, we review postingestion processing (interoception) and central integration of the tongue-gut-brain interaction, ultimately determining our sensations as well as preferences toward the wholesomeness of nutritious foods. © 2021 American Physiological Society. Compr Physiol 11:1-35, 2021.
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Affiliation(s)
- Ranier Gutierrez
- Laboratory of Neurobiology of Appetite, Department of Pharmacology, CINVESTAV, Mexico City, Mexico
| | - Sidney A Simon
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
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Zhao F, Wang S, Li Y, Wang J, Wang Y, Zhang C, Li Y, Huang L, Yu Y, Zheng J, Yu B, Pessah IN, Cao Z. Surfactant cocamide monoethanolamide causes eye irritation by activating nociceptor TRPV1 channels. Br J Pharmacol 2021; 178:3448-3462. [PMID: 33837959 PMCID: PMC11164132 DOI: 10.1111/bph.15491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/19/2020] [Accepted: 04/02/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Cocamide monoethanolamide (CMEA) is commonly used as a surfactant-foam booster in cosmetic formulations. Upon contact with the eye or other sensitive skin areas, CMEA elicits stinging and lasting irritation. We hypothesized a specific molecular interaction with TRPV1 channels by which CMEA caused eye irritation. EXPERIMENTAL APPROACH Eye irritancy was evaluated using eye-wiping tests in rabbits and mice. Intracellular Ca2+ concentrations and action potentials were measured using Ca2+ imaging and current clamp respectively. Voltage clamp, site-direct mutagenesis and molecular modelling were used to identify binding pockets for CMEA on TRPV1 channels. KEY RESULTS CMEA-induced eye irritation is ameliorated by selective ablation of TRPV1 channels.Rodents exhibit much stronger responses to CMEA than rabbits. In trigeminal ganglion neurons, CMEA induced Ca2+ influx and neuronal excitability, effects mitigated by a TRPV1 channel inhibition and absent in TRPV1 knockout neurons. In HEK-293 cells expressing TRPV1 channels, CMEA increased whole-cell currents by increasing channel open probability (EC50 = 10.2 μM), without affecting TRPV2, TRPV3, TRPV4, and TRPA1 channel activities. Lauric acid monoethanolamide (LAMEA), the most abundant constituent of CMEA, was the most efficacious and potent TRPV1 channel activator, binding to the capsaicin-binding pocket of the channel. The T550I mutants of rabbit and human TRPV1 channels exhibit much lower sensitivity to LAMEA. CONCLUSIONS AND IMPLICATION CMEA directly activates TRPV1 channels to produce eye irritation. Rabbits, the standard animal used for eye irritancy tests are poor models for evaluating human eye irritants structurally related to CMEA. Our study identifies potential alternatives to CMEA as non-irritating surfactants.
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Affiliation(s)
- Fang Zhao
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Shuangyan Wang
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Yan Li
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Jin Wang
- Department of Basic Medicine, School of Basic Medicine and Clinic Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Yujing Wang
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Chunlei Zhang
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 200025
| | - Longjiang Huang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China, 266042
| | - Ye Yu
- Department of Basic Medicine, School of Basic Medicine and Clinic Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA, 95616
| | - Boyang Yu
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
| | - Isaac N Pessah
- Department of Molecular Bioscience, School of Veterinary Medicine, University of California, Davis, California, USA, 95616
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines and Department of TCM pharmacology, School of Traditional Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China, 211198
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Mistretta CM, Bradley RM. The Fungiform Papilla Is a Complex, Multimodal, Oral Sensory Organ. CURRENT OPINION IN PHYSIOLOGY 2021; 20:165-173. [PMID: 33681545 DOI: 10.1016/j.cophys.2021.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
When solid or liquid stimuli contact the tongue tip during eating, the sensations of taste, touch and temperature are immediately evoked, and tongue function relies on these simultaneous multimodal responses. We focus on the fungiform papilla of the anterior tongue as a complex organ for taste, tactile and thermal modalities, all via chorda tympani nerve innervation from the geniculate ganglion. Rather than a review, our aim is to revise the classic archetype of the fungiform as predominantly a taste bud residence only and instead emphasize an amended concept of the papilla as a multimodal organ. Neurophysiological maps of fungiform papillae in functional receptive fields demonstrate responses to chemical, stroking and cold lingual stimuli. Roles are predicted for elaborate extragemmal nerve endings in tactile and temperature sensations, and potential functions for keratinocytes in noncanonical sensory signaling. The fungiform papilla is presented as a polymodal lingual organ, not solely a gustatory papilla.
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Affiliation(s)
- Charlotte M Mistretta
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109 United States
| | - Robert M Bradley
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109 United States
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20
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Lemon CH. Tasting temperature: neural and behavioral responses to thermal stimulation of oral mucosa. CURRENT OPINION IN PHYSIOLOGY 2021; 20:16-22. [PMID: 33937598 DOI: 10.1016/j.cophys.2020.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Temperature sensation contributes to human enjoyment of foods and beverages. The mouthfeel of warmed foods or drinking ice-cold water on a hot day are respectively pleasant and refreshing. Although historically under-studied for a role in food preference, new data have shed light on how oral temperature sensing and thermoreceptor mechanisms inside the mouth influence ingestive acceptance behaviors in rodent models used in flavor neurobiology. Moreover, recent functional data have uncovered a broad diversity of thermosensory neurons in primary afferents and brain pathways that signal oral temperature. This review will discuss some of the progress made in these areas. Ultimately, unraveling the biological basis of oral temperature sensing will be critical to reveal how thermosensory factors interact with other orosensory modalities to shape ingestive preferences. Elucidating oral thermal processing will also be key for establishing general principles of temperature coding by the nervous system.
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Affiliation(s)
- Christian H Lemon
- Department of Biology, 730 Van Vleet Oval, University of Oklahoma, Norman, OK, 73019 USA.,Institute for Biomedical Engineering, Science, and Technology, University of Oklahoma, Norman, OK, 73019 USA
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21
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MacDonald DI, Wood JN, Emery EC. Molecular mechanisms of cold pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2020; 7:100044. [PMID: 32090187 PMCID: PMC7025288 DOI: 10.1016/j.ynpai.2020.100044] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/17/2022]
Abstract
The sensation of cooling is essential for survival. Extreme cold is a noxious stimulus that drives protective behaviour and that we thus perceive as pain. However, chronic pain patients suffering from cold allodynia paradoxically experience innocuous cooling as excruciating pain. Peripheral sensory neurons that detect decreasing temperature express numerous cold-sensitive and voltage-gated ion channels that govern their response to cooling in health and disease. In this review, we discuss how these ion channels control the sense of cooling and cold pain under physiological conditions, before focusing on the molecular mechanisms by which ion channels can trigger pathological cold pain. With the ever-rising number of patients burdened by chronic pain, we end by highlighting the pressing need to define the cells and molecules involved in cold allodynia and so identify new, rational drug targets for the analgesic treatment of cold pain.
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