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Vlădescu SC, Bozorgi S, Hu S, Baier SK, Myant C, Carpenter G, Reddyhoff T. Effects of beverage carbonation on lubrication mechanisms and mouthfeel. J Colloid Interface Sci 2021; 586:142-151. [PMID: 33162047 DOI: 10.1016/j.jcis.2020.10.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 11/27/2022]
Abstract
The perception of carbonation is an important factor in beverage consumption which must be understood in order to develop healthier products. Herein, we study the effects of carbonated water on oral lubrication mechanisms involved in beverage mouthfeel and hence taste perception. Friction was measured in a compliant PDMS-glass contact simulating the tongue-palate interface (under representative speeds and loads), while fluorescence microscopy was used to visualise both the flow of liquid and oral mucosal pellicle coverage. When carbonated water is entrained into the contact, CO2 cavities form at the inlet, which limit flow and thus reduce the hydrodynamic pressure. Under mixed lubrication conditions, when the fluid film thickness is comparable to the surface roughness, this pressure reduction results in significant increases in friction (>300% greater than under non-carbonated water conditions). Carbonated water is also shown to be more effective than non-carbonated water at debonding the highly lubricious, oral mucosal pellicle, which again results in a significant increase in friction. Both these transient mechanisms of starvation and salivary pellicle removal will modulate the flow of tastants to taste buds and are suggested to be important in the experience of taste and refreshment. For example this may be one reason why flat colas taste sweeter.
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Affiliation(s)
- Sorin-Cristian Vlădescu
- Tribology Group, Department of Mechanical Engineering, Imperial College London, South Kensington, Exhibition Road, SW7 2AZ London, United Kingdom
| | - Sophie Bozorgi
- Salivary Research Unit, Faculty of Dental, Oral and Craniofacial Sciences, King's College London Dental Institute, Floor 17 Guy's Tower, London SE1 9RT, UK
| | - Songtao Hu
- Tribology Group, Department of Mechanical Engineering, Imperial College London, South Kensington, Exhibition Road, SW7 2AZ London, United Kingdom; State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Stefan K Baier
- PepsiCo Global Functions, Measurement Science, 3 Skyline Drive, Hawthorne, NY 10532, USA; School of Chemical Engineering, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Connor Myant
- Robotics and Manufacturing Group, Dyson School of Design Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Guy Carpenter
- Salivary Research Unit, Faculty of Dental, Oral and Craniofacial Sciences, King's College London Dental Institute, Floor 17 Guy's Tower, London SE1 9RT, UK
| | - Tom Reddyhoff
- Tribology Group, Department of Mechanical Engineering, Imperial College London, South Kensington, Exhibition Road, SW7 2AZ London, United Kingdom.
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Angeloni G, Masella P, Guerrini L, Spadi A, Bellumori M, Innocenti M, Parenti A. Physical and Chemical Effects of Different Working Gases in Coffee Brewing: A Case Study of Caffè Firenze. Foods 2020; 9:foods9121825. [PMID: 33316883 PMCID: PMC7762973 DOI: 10.3390/foods9121825] [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: 10/27/2020] [Revised: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 12/04/2022] Open
Abstract
(1) Background: Recently, a new espresso extraction method, Caffè Firenze, has been developed, which uses gas at operating pressures of 20 bar to obtain abundant, persistent foam. The experiment aimed to evaluate the effect of using six gases (air, argon, nitrogen, carbon dioxide, carbon/nitrogen mix, and nitrous oxide) on the foam and liquid coffee. (2) Methods: Foam volume, persistence, sugar retention time, color, and rheological properties were measured. Volatile organic compounds were also evaluated. Analyses were also carried out on the liquid coffee to determine caffeine and chlorogenic acid concentrations. (3) Results: The analysis of variance revealed significant differences between the gases for all parameters. Multivariate analysis identified three groups of gases: the first comprised air, N2, and Ar; the second CO2 and N2O; and the third comprised samples extracted with CO2/N2 mix. (4) Conclusions: The choice of gas significantly influences the drink’s chemical-physical characteristics and is fundamental for product diversification.
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Affiliation(s)
- Giulia Angeloni
- DAGRI, Department of Agriculture, Food, Environment and Forestry, University of Florence, Piazzale delle Cascine, 16, 50144 Firenze, Italy; (P.M.); (L.G.); (A.S.); (A.P.)
- Correspondence:
| | - Piernicola Masella
- DAGRI, Department of Agriculture, Food, Environment and Forestry, University of Florence, Piazzale delle Cascine, 16, 50144 Firenze, Italy; (P.M.); (L.G.); (A.S.); (A.P.)
| | - Lorenzo Guerrini
- DAGRI, Department of Agriculture, Food, Environment and Forestry, University of Florence, Piazzale delle Cascine, 16, 50144 Firenze, Italy; (P.M.); (L.G.); (A.S.); (A.P.)
| | - Agnese Spadi
- DAGRI, Department of Agriculture, Food, Environment and Forestry, University of Florence, Piazzale delle Cascine, 16, 50144 Firenze, Italy; (P.M.); (L.G.); (A.S.); (A.P.)
| | - Maria Bellumori
- Department of Neurofarba, Division of Pharmaceutical and Nutraceutical Sciences, University of Florence, via Ugo Schiff, 6, 50137 Sesto Fiorentino, Italy; (M.B.); (M.I.)
| | - Marzia Innocenti
- Department of Neurofarba, Division of Pharmaceutical and Nutraceutical Sciences, University of Florence, via Ugo Schiff, 6, 50137 Sesto Fiorentino, Italy; (M.B.); (M.I.)
| | - Alessandro Parenti
- DAGRI, Department of Agriculture, Food, Environment and Forestry, University of Florence, Piazzale delle Cascine, 16, 50144 Firenze, Italy; (P.M.); (L.G.); (A.S.); (A.P.)
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Abstract
Mouthfeel refers to the physical or textural sensations in the mouth caused by foods and beverages that are essential to the acceptability of many edible products. The sensory subqualities contributing to mouthfeel are often chemogenic in nature and include heat, burning, cooling, tingling, and numbing. These "chemesthetic" sensations are a result of the chemical activation of receptors that are associated with nerve fibers mediating pain and mechanotransduction. Each of these chemesthetic sensations in the oral cavity are transduced in the nervous system by a combination of different molecular channels/receptors expressed on trigeminal nerve fibers that innervate the mouth and tongue. The molecular profile of these channels and receptors involved in mouthfeel include many transient receptor potential channels, proton-sensitive ion channels, and potassium channels to name a few. During the last several years, studies using molecular and physiological approaches have significantly expanded and enhanced our understanding of the neurobiological basis for these chemesthetic sensations. The purpose of the current review is to integrate older and newer studies to present a comprehensive picture of the channels and receptors involved in mouthfeel. We highlight that there still continue to be important gaps in our overall knowledge on flavor integration and perception involving chemesthetic sensations, and these gaps will continue to drive future research direction and future investigation.
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Affiliation(s)
- Christopher T Simons
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
| | - Earl Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
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McMahon KM, Culver C, Ross CF. The production and consumer perception of sparkling wines of different carbonation levels. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/09571264.2017.1288092] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | | | - Carolyn F. Ross
- School of Food Science, Washington State University, Pullman, WA, USA
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Magara J, Michou E, Raginis-Zborowska A, Inoue M, Hamdy S. Exploring the effects of synchronous pharyngeal electrical stimulation with swallowing carbonated water on cortical excitability in the human pharyngeal motor system. Neurogastroenterol Motil 2016; 28:1391-400. [PMID: 27061591 DOI: 10.1111/nmo.12839] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/17/2016] [Indexed: 01/30/2023]
Abstract
BACKGROUND Previous reports have revealed that excitation of human pharyngeal motor cortex can be induced by pharyngeal electrical stimulation (PES) and swallowing carbonated water (CW). This study investigated whether combining PES with swallowing (of still water, SW or CW) can potentiate this excitation in either cortical and/or brain stem areas assessed with transcranial and transcutaneous magnetic stimulation (TMS). METHODS Fourteen healthy volunteers participated and were intubated with an intraluminal catheter to record pharyngeal electromyography and deliver PES. Each participant underwent baseline corticopharyngeal, hand and craniobulbar motor-evoked potential (MEP) measurements. Subjects were then randomized to receive each of four 10-min interventions (PES only, ShamPES+CW, PES+CW, and PES+SW). Corticobulbar, craniobulbar and hand MEPs were then remeasured for up to 60 min and data analyzed using anova and post hoc t-tests. KEY RESULTS A two-way rmanova for Interventions × Time-point showed a significant corticopharyngeal interaction (p = 0.010). One-way anova with post hoc t-tests indicated significant cortical changes with PES only at 45 (p = 0.038) and 60 min (p = 0.023) and ShamPES+CW immediately (p = 0.008) but not with PES+CW or PES+SW. By contrast, there were immediate craniobulbar amplitude changes only with PES+CW (p = 0.020) which were not sustained. CONCLUSIONS & INFERENCES We conclude that only PES produced long-term changes in corticopharyngeal excitability whereas combination stimuli were less effective. Our data suggest that PES alone rather than in combination, may be better for the patients who have difficulty in performing voluntary swallows.
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Affiliation(s)
- J Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Salford, UK
| | - E Michou
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Salford, UK
| | - A Raginis-Zborowska
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Salford, UK
| | - M Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - S Hamdy
- Centre for Gastrointestinal Sciences, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester, Salford, UK
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Risso P, Maggioni E, Olivero N, Gallace A. The association between the colour of a container and the liquid inside: An experimental study on consumers’ perception, expectations and choices regarding mineral water. Food Qual Prefer 2015. [DOI: 10.1016/j.foodqual.2015.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wise PM, Bryant B. The Effect of Temperature and Menthol on Carbonation Bite. Chem Senses 2014; 39:571-82. [DOI: 10.1093/chemse/bju027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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The influence of bubbles on the perception carbonation bite. PLoS One 2013; 8:e71488. [PMID: 23990956 PMCID: PMC3749224 DOI: 10.1371/journal.pone.0071488] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 06/28/2013] [Indexed: 11/19/2022] Open
Abstract
Although many people naively assume that the bite of carbonation is due to tactile stimulation of the oral cavity by bubbles, it has become increasingly clear that carbonation bite comes mainly from formation of carbonic acid in the oral mucosa. In Experiment 1, we asked whether bubbles were in fact required to perceive carbonation bite. Subjects rated oral pungency from several concentrations of carbonated water both at normal atmospheric pressure (at which bubbles could form) and at 2.0 atmospheres pressure (at which bubbles did not form). Ratings of carbonation bite under the two pressure conditions were essentially identical, indicating that bubbles are not required for pungency. In Experiment 2, we created controlled streams of air bubbles around the tongue in mildly pungent CO2 solutions to determine how tactile stimulation from bubbles affects carbonation bite. Since innocuous sensations like light touch and cooling often suppress pain, we predicted that bubbles might reduce rated bite. Contrary to prediction, air bubbles flowing around the tongue significantly enhanced rated bite, without inducing perceived bite in blank (un-carbonated) solutions. Accordingly, though bubbles are clearly not required for carbonation bite, they may well modulate perceived bite. More generally, the results show that innocuous tactile stimulation can enhance chemogenic pain. Possible physiological mechanisms are discussed.
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Eugenol and carvacrol induce temporally desensitizing patterns of oral irritation and enhance innocuous warmth and noxious heat sensation on the tongue. Pain 2013; 154:2078-2087. [PMID: 23791894 DOI: 10.1016/j.pain.2013.06.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 05/29/2013] [Accepted: 06/17/2013] [Indexed: 11/20/2022]
Abstract
Eugenol and carvacrol, from the spices clove and oregano, respectively, are agonists of TRPV3, which is implicated in transduction of warmth and possibly heat pain. We investigated the temporal dynamics of lingual irritation elicited by these agents, and their effects on innocuous warmth and heat pain, using a half-tongue method in human subjects. The irritant sensation elicited by both eugenol and carvacrol decreased across repeated applications at a 1-minute interstimulus interval (self-desensitization) which persisted for at least 10 minutes. Both agents also cross-desensitized capsaicin-evoked irritation. Eugenol and carvacrol significantly increased the magnitude of perceived innocuous warmth (44 °C) for >10 minutes, and briefly (<5 minutes) enhanced heat pain elicited by a 49 °C stimulus. Similar albeit weaker effects were observed when thermal stimuli were applied after the tongue had been desensitized by repeated application of eugenol or carvacrol, indicating that the effect is not due solely to summation of chemoirritant and thermal sensations. Neither chemical affected sensations of innocuous cool or cold pain. A separate group of subjects was asked to subdivide eugenol and carvacrol irritancy into subqualities, the most frequently reported being numbing and warmth, with brief burning, stinging/pricking, and tingle, confirming an earlier study. Eugenol, but not carvacrol, reduced detection of low-threshold mechanical stimuli. Eugenol and carvacrol enhancement of innocuous warmth may involve sensitization of thermal gating of TRPV3 expressed in peripheral warm fibers. The brief heat hyperalgesia following eugenol may involve a TRPV3-mediated enhancement of thermal gating of TRPV1 expressed in lingual polymodal nociceptors.
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Michou E, Mastan A, Ahmed S, Mistry S, Hamdy S. Examining the role of carbonation and temperature on water swallowing performance: a swallowing reaction-time study. Chem Senses 2012; 37:799-807. [PMID: 22843761 DOI: 10.1093/chemse/bjs061] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Various therapeutic approaches for dysphagia management are based on modifications of bolus properties to change swallowing biomechanics and increase swallowing safety. Limited evidence exists for the effects of carbonation and bolus temperature on swallowing behavior. Here, we investigated the effects of carbonation and temperature on swallowing behavior using a novel automated and complex swallowing reaction time task via pressure signal recordings in the hypopharynx. Healthy participants (n = 39, 27.7±5 years old) were randomized in two different experiments and asked to perform 10 normal-paced swallows, 10 fast-paced swallows, and 10 challenged swallows within a predetermined time-window of carbonated versus still water (experiment 1) and of cold (4 °C) versus hot (45 °C) versus room temperature (21 °C) water (experiment 2). Quantitative measurements of latencies and percentage of successful challenged swallows were collected and analyzed nonparametrically. An increase in successfully performed challenged swallowing task was observed with carbonated water versus still water (P = 0.021), whereas only cold water shortened the latencies of normally paced swallows compared with room (P = 0.001) and hot (P = 0.004) temperatures. Therefore, it appears that chemothermal stimulation with carbonation and cold are most effective at modulating water swallowing, which in part is likely to be driven by central swallowing afferent activity.
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Affiliation(s)
- Emilia Michou
- School of Translational Medicine-Inflammation Sciences, Faculty of Medical and Human Sciences, University of Manchester (part of the Manchester Academic Health Sciences Centre (MAHSC)), Salford Royal Hospital, Eccles Old Road, Salford M6 8HD, UK
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Effects of carbonated liquids on oropharyngeal swallowing measures in people with neurogenic dysphagia. Dysphagia 2011; 27:240-50. [PMID: 21822745 DOI: 10.1007/s00455-011-9359-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 07/19/2011] [Indexed: 10/17/2022]
Abstract
Aspiration is common in adults with neurogenic dysphagia and pharyngeal delay. This can lead to dehydration, malnutrition, and aspiration pneumonia. Diet modifications aimed at reducing thin liquid aspiration are partially successful or unpalatable or both. Carbonated liquids show some potential in influencing swallowing behavior. However, there is a paucity of evidence to support this intervention. This study compares the effects of carbonated thin liquids (CTL) with that of noncarbonated thin liquids (NCTL) on oropharyngeal swallowing in adults with neurogenic dysphagia and examines the palatability of the CTL stimulus. Seventeen people with pharyngeal delay attended for videofluoroscopy (VFSS). Outcome measures were oral transit time (OTT), pharyngeal transit time (PTT), stage transition duration (STD), initiation of the pharyngeal swallow (IPS), penetration-aspiration scale (PENASP), and pharyngeal retention (PR). A modification of Quartermaster Hedonic Scale (AQHS) was employed to assess palatability of the CTL. CTL vs. NCTL significantly decreased penetration and aspiration on 5-ml (P = 0.028) and 10-ml (P = 0.037) swallows. CTL had no significant effect on OTT, PTT, IPS, and PR for any volume of bolus. Only one participant disliked the CTL stimulus. These findings support the hypothesis that oropharyngeal swallowing can be modulated in response to sensory stimuli. Implications for research and clinical practice are discussed.
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Dunkel A, Hofmann T. Carbonic anhydrase IV mediates the fizz of carbonated beverages. Angew Chem Int Ed Engl 2010; 49:2975-7. [PMID: 20235256 DOI: 10.1002/anie.200906978] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andreas Dunkel
- Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Strasse 34, 85354 Freising, Deutschland
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Dunkel A, Hofmann T. Carboanhydrase IV vermittelt das Prickeln der Kohlensäure in Getränken. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200906978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chandrashekar J, Yarmolinsky D, von Buchholtz L, Oka Y, Sly W, Ryba NJP, Zuker CS. The taste of carbonation. Science 2009; 326:443-5. [PMID: 19833970 PMCID: PMC3654389 DOI: 10.1126/science.1174601] [Citation(s) in RCA: 254] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Carbonated beverages are commonly available and immensely popular, but little is known about the cellular and molecular mechanisms underlying the perception of carbonation in the mouth. In mammals, carbonation elicits both somatosensory and chemosensory responses, including activation of taste neurons. We have identified the cellular and molecular substrates for the taste of carbonation. By targeted genetic ablation and the silencing of synapses in defined populations of taste receptor cells, we demonstrated that the sour-sensing cells act as the taste sensors for carbonation, and showed that carbonic anhydrase 4, a glycosylphosphatidylinositol-anchored enzyme, functions as the principal CO2 taste sensor. Together, these studies reveal the basis of the taste of carbonation as well as the contribution of taste cells in the orosensory response to CO2.
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Affiliation(s)
- Jayaram Chandrashekar
- Howard Hughes Medical Institute and Departments of Neurobiology and Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
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Sudo S, Sudo M, Simons CT, Dessirier JM, Iodi Carstens M, Carstens E. Activation of neurons in trigeminal caudalis by noxious oral acidic or salt stimuli is not reduced by amiloride. Brain Res 2003; 969:237-43. [PMID: 12676384 DOI: 10.1016/s0006-8993(03)02341-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We investigated the possible role of amiloride-sensitive ion channels of the ENaC/DEGenerin superfamily in the activation of trigeminal nociceptive neurons elicited by noxious chemical stimulation of the oral mucosa using two methodologies, single-unit recording and c-fos immunohistochemistry. In pentobarbital-anesthetized rats, single-unit recordings were made from neurons in superficial laminae of dorsomedial trigeminal subnucleus caudalis (Vc) that responded to noxious thermal and chemical stimuli applied to the dorsal tongue. Successive application of each of three chemicals (250 mM pentanoic acid, n=6 units; 250 mM citric acid, n=8; 5 M NaCl, n=6) evoked responses that were not affected following topical application of amiloride (1 mM). In separate experiments, pentobarbital-anesthetized rats received one of the following stimuli delivered to the dorsal tongue: 250 mM pentanoic acid (n=6); 1 mM amiloride followed by 250 mM pentanoic (N=6); 5 M NaCl (n=5); or 1 mM amiloride followed by 5 M NaCl (n=5). Two hours later they were perfused with 4% paraformaldehyde and the brain stems processed for c-fos immunoreactivity. Both pentanoic acid and 5 M NaCl evoked similar numbers and patterns of fos-like immunoreactivity (FLI) in dorsomedial Vc and other brain stem regions, with no significant difference in counts of FLI in animals pretreated with amiloride. These results suggest that amiloride-sensitive Na(+) channels are not essential in mediating the activation of intraoral trigeminal nociceptors.
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Affiliation(s)
- Satoko Sudo
- Department of Anesthesiology and Resuscitology, Ehime University School of Medicine, Ehime, Shigenobu, Japan
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It hurts so good: oral irritation by spices and carbonated drinks and the underlying neural mechanisms. Food Qual Prefer 2002. [DOI: 10.1016/s0950-3293(01)00067-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sudo S, Sudo M, Simons CT, Dessirier JM, Carstens E. Sensitization of trigeminal caudalis neuronal responses to intraoral acid and salt stimuli and desensitization by nicotine. Pain 2002; 98:277-286. [PMID: 12127029 DOI: 10.1016/s0304-3959(02)00025-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In human studies, repeated intraoral application of strong acidic or salt stimuli induces irritation that progressively increases across trials (sensitization), whereas irritation elicited by nicotine progressively decreases (desensitization). We investigated whether nociceptive neurons in trigeminal subnucleus caudalis (Vc) exhibit increasing or decreasing patterns of firing to the intraoral application of these irritants. In rats anesthetized with halothane and thiopental, single-unit recordings were made from nociceptive neurons in superficial layers of dorsomedial Vc that responded to mechanical and noxious thermal and chemical stimulation of the tongue. NaCl (5M), citric acid (300 mM), pentanoic acid (300 mM) or nicotine (600 mM) were separately delivered to the tongue by constant flow (0.32 ml/min) for 15 or 25 min. NaCl, citric acid and pentanoic acid each elicited a progressive, significant increase in Vc neuronal firing over the initial 10 min to a plateau level that was maintained for the stimulus duration. Nicotine induced a significant increase in firing rate of Vc neurons within 6 min, followed by a decline back to the baseline level over the ensuing 10 min. Following a rest period, reapplication of nicotine no longer activated Vc neurons, indicative of self-desensitization. We additionally tested for nicotine cross-desensitization to acid. After recording the responses of Vc neurons to pentanoic acid and noxious heat, nicotine was then applied for 15 min. Post-nicotine responses to pentanoic acid were markedly reduced (to 13% of control), indicative of cross-desensitization; responses to noxious heat were also reduced to a lesser degree (to 71% of control). The progressive increase in Vc neuronal firing elicited by NaCl and acid, and the decline in firing after initial nicotinic excitation, resemble psychophysical patterns of sensitization and desensitization, respectively, and support the involvement of Vc neurons in the signaling of oral irritant sensations.
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Affiliation(s)
- Satoko Sudo
- Department of Anesthesiology and Resuscitology, Ehime University School of Medicine, Ehime, Shigenobu, Japan Department of Food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA Unilever Research US, Edgewater, NY 07020, USA Section of Neurobiology, Physiology & Behavior, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
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