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Ramudit AE, Feldmeyer A, Johnson A, Ennis JM. Sensory interaction effects between capsicum heat and seasoning ingredients applied to unsalted potato chips. Food Qual Prefer 2022. [DOI: 10.1016/j.foodqual.2022.104682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2
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Yu T, Wilson CE, Stratford JM, Finger TE. Genetic Deletion of TrpV1 and TrpA1 Does Not Alter Avoidance of or Patterns of Brainstem Activation to Citric Acid in Mice. Chem Senses 2020; 45:573-579. [PMID: 32572463 DOI: 10.1093/chemse/bjaa043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Exposure of the oral cavity to acidic solutions evokes not only a sensation of sour, but also of sharp or tangy. Acidic substances potentially stimulate both taste buds and acid-sensitive mucosal free nerve endings. Mice lacking taste function (P2X2/P2X3 double-KO mice) refuse acidic solutions similar to wildtype (WT) mice and intraoral infusion of acidic solutions in these KO animals evokes substantial c-Fos activity within orosensory trigeminal nuclei as well as of the nucleus of the solitary tract (nTS) (Stratford, Thompson, et al. 2017). This residual acid-evoked, non-taste activity includes areas that receive inputs from trigeminal and glossopharyngeal peptidergic (CGRP-containing) nerve fibers that express TrpA1 and TrpV1 both of which are activated by low pH. We compared avoidance responses in WT and TrpA1/V1 double-KO (TRPA1/V1Dbl-/-) mice in brief-access behavioral assay (lickometer) to 1, 3, 10, and 30 mM citric acid, along with 100 µM SC45647 and H2O. Both WT and TRPA1/V1Dbl-/- show similar avoidance, including to higher concentrations of citric acid (10 and 30 mM; pH 2.62 and pH 2.36, respectively), indicating that neither TrpA1 nor TrpV1 is necessary for the acid-avoidance behavior in animals with an intact taste system. Similarly, induction of c-Fos in the nTS and dorsomedial spinal trigeminal nucleus was similar in the WT and TRPA1/V1Dbl-/- animals. Taken together these results suggest non-TrpV1 and non-TrpA1 receptors underlie the residual responses to acids in mice lacking taste function.
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Affiliation(s)
- Tian Yu
- Rocky Mountain Taste & Smell Center, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Courtney E Wilson
- Rocky Mountain Taste & Smell Center, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Jennifer M Stratford
- Rocky Mountain Taste & Smell Center, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Thomas E Finger
- Rocky Mountain Taste & Smell Center, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
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Nachtigal D, Andrew K, Green BG. Selective Effects of Temperature on the Sensory Irritation but not Taste of NaCl and Citric Acid. Chem Senses 2019; 44:61-68. [PMID: 30418541 DOI: 10.1093/chemse/bjy072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigated the effect of temperature on taste and chemesthetic sensations produced by the prototypical salty and sour stimuli NaCl and citric acid. Experiment 1 measured the perceived intensity of irritation (burning, stinging) and taste (saltiness, sourness) produced on the tongue tip by brief (3 s) exposures to suprathreshold concentrations of NaCl and citric acid at 3 different temperatures (12, 34, and 42 °C). No significant effects of temperature were found on the taste or sensory irritation of either stimulus. Experiment 2 investigated the potential effects of temperature on sensory irritation at peri-threshold concentrations and its sensitization over time. Measurements were again made on the tongue tip at the same 3 temperatures. Heating was found to enhance the perception of irritation at peri-threshold concentrations for both stimuli, whereas cooling suppressed sensitization of irritation for NaCl but not for citric acid. These results (i) confirm prior evidence that perception of suprathreshold salty and sour tastes are independent of temperature; (ii) demonstrate that heat has only weak effects on sensory irritation produced by brief exposures to NaCl and citric acid; and (iii) suggest that sensitization of the irritation produced by NaCl and citric acid occur via different peripheral mechanisms that have different thermal sensitivities. Overall, the results are consistent with involvement of the heat-sensitive channel TRPV1 in the sensory irritation of both stimuli together with one or more additional channels (e.g., acid-sensing channel, epithelial sodium channel, TRPA1) that are insensitive to heat and may possibly be sensitive to cooling.
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Affiliation(s)
- Danielle Nachtigal
- The John B. Pierce Laboratory, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Kendra Andrew
- The John B. Pierce Laboratory, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Barry G Green
- The John B. Pierce Laboratory, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Surgery (Otolaryngology), Yale School of Medicine, Yale University, New Haven, CT, USA
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Variation in Orosensory Responsiveness to Alcoholic Beverages and Their Constituents—the Role of the Thermal Taste Phenotype. CHEMOSENS PERCEPT 2019. [DOI: 10.1007/s12078-019-09266-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
The trigeminal sensory nerve fiber branches supply afferent information from the skin and mucous membranes of the face and head and the oral cavity regarding information on temperature, touch, and pain. Under normal conditions, the trigeminal nerve serves to provide important information from nerve fibers and tissues using specialized receptors sensitive for irritant and painful stimuli. The current scientific consensus indicates that nerve endings responsible for chemical and thermal sensitivity of the skin and mucous membranes are the same nerves responsible for nociception. This "chemesthetic sense" allows many vertebrates to detect chemical agonists that induce sensations such as touch, burning, stinging, tingling, or changes in temperature. Research has been under way for many years to determine how exposure of the oral and/or nasal cavity to compounds that elicit pungent or irritant sensations can produce these sensations. In addition, these chemicals can alter other sensory information such as taste and smell to affect the flavor of foods and beverages. We now know that these 'chemesthetic molecules' are agonists of molecular receptors, which exist on primary afferent nerve fibers that innervate the orofacial area. However, under pathophysiologic conditions, over- or underexpression or activity of these receptors may lead to painful orotrigeminal syndromes. Some of these individual receptors are discussed in detail, including transient receptor potential channels and acid sensing ion channels, among others.
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Affiliation(s)
- Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States. //
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The cellular mechanism for water detection in the mammalian taste system. Nat Neurosci 2017; 20:927-933. [DOI: 10.1038/nn.4575] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 04/30/2017] [Indexed: 12/20/2022]
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Ledeker CN, Suwonsichon S, Chambers DH, Adhikari K. Comparison of sensory attributes in fresh mangoes and heat-treated mango purées prepared from Thai cultivars. Lebensm Wiss Technol 2014. [DOI: 10.1016/j.lwt.2013.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Guirao M, Greco Driano EJ, Evin D, Calviño A. Psychophysical assessments of sourness in citric acid-ethanol mixtures. Percept Mot Skills 2014; 117:868-80. [PMID: 24665803 DOI: 10.2466/24.27.pms.117x29z3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effect of ethanol in modulating the intensity and duration of the perceived sourness induced by citric acid was studied. Magnitude Estimation-Converging Limits method was applied to rate the sourness of seven solutions (3-70 mM) of citric acid in aqueous solution presented alone and mixed with 8% V/V or 15% V/V ethanol. Dynamic sourness ratings of 5, 15, and 45 mM citric acid alone and mixed with the same two ethanol levels were assessed by the Time Intensity Method (TI). Results were consistent with both methods. Sourness changed with citric acid concentration and ethanol levels. From TI measurements, a similar interactive pattern was obtained for parameters as duration, area under the curve, peak and average intensity.
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Torre P, Arana I, Ortigosa M, Ibáñez FC. Search and Validation of Acidity References in Sensory Evaluation of Pepper. J SENS STUD 2012. [DOI: 10.1111/joss.12003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paloma Torre
- Department of Environmental Sciences; Universidad Pública de Navarra; Campus Arrosadía 31006 Pamplona Navarra Spain
| | - Inés Arana
- Department of Environmental Sciences; Universidad Pública de Navarra; Campus Arrosadía 31006 Pamplona Navarra Spain
| | - María Ortigosa
- Department of Environmental Sciences; Universidad Pública de Navarra; Campus Arrosadía 31006 Pamplona Navarra Spain
| | - Francisco C. Ibáñez
- Department of Environmental Sciences; Universidad Pública de Navarra; Campus Arrosadía 31006 Pamplona Navarra Spain
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Humbert IA, Joel S. Tactile, gustatory, and visual biofeedback stimuli modulate neural substrates of deglutition. Neuroimage 2011; 59:1485-90. [PMID: 21872665 DOI: 10.1016/j.neuroimage.2011.08.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022] Open
Abstract
It has been well established that swallowing kinematics are modified with different forms of exogenous and endogenous input, however the underlying neural substrates associated with these effects are largely unknown. Our objective was to determine whether the swallowing BOLD response is modulated with heightened sensory modalities (taste, cutaneous electrical stimulation, and visual biofeedback) compared to water ingestion (control) in healthy adults across the age span. Habituation and sensitization were also examined for each sensory condition. Our principal findings are that each sensory swallowing condition activated components of the swallowing cortical network, plus regions associated with the particular sensory modality (i.e. primarily frontal motor planning and integration areas with visual condition). Overall, the insula was most commonly active among the sensory modalities. We also discuss gradual increases and decreases in BOLD signal with repeated exposures for each condition. We conclude that both stimulus- and intention-based inputs have unique cortical swallowing networks relative to their modality. This scientific contribution advances our understanding of the mechanisms of normal swallowing cortical control and has the potential to impact clinical uses of these modalities in treatments for neurogenic dysphagia.
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Affiliation(s)
- Ianessa A Humbert
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, 98 North Broadway, Suite 403, Baltimore, MD 21231, USA.
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Crogan NL. Managing Xerostomia in Nursing Homes: Pilot Testing of the Sorbet Increases Salivation Intervention. J Am Med Dir Assoc 2011; 12:212-6. [DOI: 10.1016/j.jamda.2010.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 06/14/2010] [Indexed: 11/28/2022]
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Albin KC, Simons CT. Psychophysical evaluation of a sanshool derivative (alkylamide) and the elucidation of mechanisms subserving tingle. PLoS One 2010; 5:e9520. [PMID: 20209090 PMCID: PMC2831077 DOI: 10.1371/journal.pone.0009520] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 02/09/2010] [Indexed: 11/18/2022] Open
Abstract
Previous studies investigated the neural and molecular underpinnings of the tingle sensation evoked by sanshool and other natural or synthetic alkylamides. Currently, we sought to characterize the psychophysical properties associated with administration of these compounds. Like other chemesthetic stimuli, the synthetic tingle analog isobutylalkylamide (IBA) evoked a sensation that was temporally dynamic. Repeated IBA application at short (30 sec) interstimulus intervals (ISI) resulted in a tingle sensation that increased across trials. Application at longer ISIs (approximately 30 min) resulted in a sensation of decreased intensity consistent with self-desensitization. Prior treatment with the TRPV1 or TRPA1 agonists, capsaicin and mustard oil did not cross-desensitize the tingle sensation evoked by IBA suggesting that neither TRPV1 nor TRPA1 participate in the transduction mechanism sub-serving tingle. When evaluated over 30-min time period, lingual IBA evoked a sensation that was described initially as tingling and pungent but after approximately 15 min, as a cooling sensation. Further, we found that the sensation evoked by lingual IBA was potentiated by simultaneous application of cold (0 degrees C) and cool (21 degrees C) thermal stimuli but was unaffected by warm (33 degrees C) and hot (41 degrees C) temperatures. Finally, to test the hypothesis that the tingling sensation is subserved by the activation of mechanosensitve fibers, we evaluated lingual tactile thresholds in the presence and absence of lingual IBA. The presence of IBA significantly raised lingual tactile thresholds, whereas capsaicin did not, identifying a role for mechanosensitive fibers in conveying the tingle sensation evoked by sanshool-like compounds. Collectively, these results show that lingual alkylamide evokes a complex sensation that is temporally dynamic and consistent with in vitro and in vivo experiments suggesting these compounds activate mechanosensitve neurons via blockade of KCNK two-pore potassium channels to induce the novel tingling sensation.
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Affiliation(s)
- Kelly C. Albin
- Givaudan Flavors Corporation, Cincinnati, Ohio, United States of America
- School of Medicine, University of California San Diego, San Diego, California, United States of America
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Hewson L, Hollowood T, Chandra S, Hort J. Gustatory, Olfactory and Trigeminal Interactions in a Model Carbonated Beverage. CHEMOSENS PERCEPT 2009. [DOI: 10.1007/s12078-009-9043-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Verhagen JV, Engelen L. The neurocognitive bases of human multimodal food perception: sensory integration. Neurosci Biobehav Rev 2006; 30:613-50. [PMID: 16457886 DOI: 10.1016/j.neubiorev.2005.11.003] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2005] [Revised: 11/23/2005] [Accepted: 11/23/2005] [Indexed: 11/30/2022]
Abstract
This review addresses a fundamental neuroscientific question in food perception: how multimodal features of food are integrated. Much research and conceptualization has emerged related to multisensory integration in vision, audition and somatosensation, while it remains poorly understood and researched within the chemical and mouth feel senses. This review aims to bridge this gap. We discuss the main concepts in the fields of auditory, visual and somatosensory multisensory integration and relate them to oral-sensory (gustatory and somatosensory) and olfactory (orolfactory) interactions. We systematically review the psychophysical literature pertaining to intra- and intermodal interactions related to food perception, while making explicit distinctions between peripheral and central interactions. As the neural bases of crossmodal orolfaction currently are poorly understood, we introduce several plausible neuroscientific models, which provide a framework for further neuroscientific exploration in this area. We are guided by a new meta-analysis of the odor-taste neuroimaging literature, as well as by single-unit, anatomical and psychophysical studies. Finally, we propose strong involvement of recurrent neural networks in multisensory integration and make suggestions for future research.
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Affiliation(s)
- Justus V Verhagen
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
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Boucher Y, Simons CT, Faurion A, Azérad J, Carstens E. Trigeminal modulation of gustatory neurons in the nucleus of the solitary tract. Brain Res 2003; 973:265-74. [PMID: 12738070 DOI: 10.1016/s0006-8993(03)02526-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Electrophysiological methods were used to investigate the effects of trigeminal nerve stimulation or transection on responses of single gustatory neurons in the nucleus of the solitary tract (NTS) to tastants (NaCl, sucrose, citric acid, monosodium glutamate) in pentobarbital-anesthetized rats. Unilateral transection of the lingual nerve, or the mandibular branch of the trigeminal nerve, resulted in significant reductions (by 21 and 29%, respectively; P<0.01) in tastant-evoked responses, with no further effect following bilateral transection. Electrical stimulation of the central cut end of the mandibular nerve directly excited nine of 14 gustatory NTS units. For these units, central mandibular stimulation facilitated the tastant-evoked responses in six, depressed responses in three, and had no effect in five. Facilitation of tastant-evoked responses peaked 4 min after mandibular stimulation and recovered within 8 min. Electrical stimulation of the peripheral cut end of the mandibular nerve significantly reduced tastant-evoked responses in nine other NTS units, with a maximal reduction at 4 min post-stimulation followed by recovery. Stimulation of the superior cervical sympathetic ganglion did not affect NTS tastant-evoked responses. These results suggest the presence of complex central modulation of NTS neurons by trigeminal afferents, as well as a peripheral depressant effect on gustatory processing possibly mediated via neuropeptide release from trigeminal nerve endings in the tongue.
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Affiliation(s)
- Yves Boucher
- UFR d'Odontologie, 5 Rue Garancière, 75006 Paris, France
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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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Vitkov L, Weitgasser R, Hannig M, Fuchs K, Krautgartner WD. Candida-induced stomatopyrosis and its relation to diabetes mellitus. J Oral Pathol Med 2003; 32:46-50. [PMID: 12558958 DOI: 10.1034/j.1600-0714.2003.00020.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Glycaemic disorders and oral candidosis can be accompanied by burning mouth sensations. However, no clear relation between all three disorders is known. METHODS Seventy-two native Upper-Austrians with burning mouth sensations were examined and smears for Candida estimation were taken from the spots where the sensations were felt. All patients with previously unknown diabetes mellitus (DM) were subjected to an oral glucose tolerance test (OGTT). Use of glucocorticoid-containing anti-asthmatic sprays and the body mass index (BMI) were determined. RESULTS Of the examined non-inhalers of sprays, 52% had increased candidal density. A correlation between that increase and type 2 DM was found. The burning sensations in all patients with increased candidal density subsided completely after anti-mycotic therapy. CONCLUSION The perception of burning sensations was hypothesised to occur via stimulation of the capsaicin (vanilloid) receptor by Candida metabolites. The Candida-induced stomatopyrosis should be regarded as a single symptom indicating (predisposition to or established) type 2 DM in non-inhalers of the concerned population.
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Affiliation(s)
- Ljubomir Vitkov
- Department of Electron Microscopy, University of Salzburg, Salzburg, Austria.
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Ugawa S, Ueda T, Ishida Y, Nishigaki M, Shibata Y, Shimada S. Amiloride-blockable acid-sensing ion channels are leading acid sensors expressed in human nociceptors. J Clin Invest 2002; 110:1185-90. [PMID: 12393854 PMCID: PMC150796 DOI: 10.1172/jci15709] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many painful inflammatory and ischemic conditions such as rheumatoid arthritis, cardiac ischemia, and exhausted skeletal muscles are accompanied by local tissue acidosis. In such acidotic states, extracellular protons provoke the pain by opening cation channels in nociceptors. It is generally believed that a vanilloid receptor subtype-1 (VR1) and an acid-sensing ion channel (ASIC) mediate the greater part of acid-induced nociception in mammals. Here we provide evidence for the involvement of both channels in acid-evoked pain in humans and show their relative contributions to the nociception. In our psychophysical experiments, direct infusion of acidic solutions (pH > or = 6.0) into human skin caused localized pain, which was blocked by amiloride, an inhibitor of ASICs, but not by capsazepine, an inhibitor of VR1. Under more severe acidification (pH 5.0) amiloride was less effective in reducing acid-evoked pain. In addition, capsazepine had a partial blocking effect under these conditions. Amiloride itself neither blocked capsaicin-evoked localized pain in human skin nor inhibited proton-induced currents in VR1-expressing Xenopus oocytes. Our results suggest that ASICs are leading acid sensors in human nociceptors and that VR1 participates in the nociception mainly under extremely acidic conditions.
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Affiliation(s)
- Shinya Ugawa
- Department of Anatomy II, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
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Ugawa S, Ueda T, Ishida Y, Nishigaki M, Shibata Y, Shimada S. Amiloride-blockable acid-sensing ion channels are leading acid sensors expressed in human nociceptors. J Clin Invest 2002. [DOI: 10.1172/jci0215709] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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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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Dessirier JM, O'Mahony M, Iodi-Carstens M, Yao E, Carstens E. Oral irritation by sodium chloride: sensitization, self-desensitization, and cross-sensitization to capsaicin. Physiol Behav 2001; 72:317-24. [PMID: 11274673 DOI: 10.1016/s0031-9384(00)00412-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Psychophysical methods were used to investigate the irritant sensory properties of concentrated NaCl. The first experiment investigated potential sensitization and desensitization properties. Subjects rated the intensity of the irritation elicited by 10 successive applications of 5 M NaCl on one side of the dorsal surface of the tongue. The mean irritant sensation increased significantly across trials, consistent with sensitization. To test for self- and cross-desensitization effects of unilateral sequential stimulation with NaCl followed by a 10-min rest period, either 5 M NaCl or 10 microM capsaicin was applied bilaterally. In a two-alternative forced-choice (2-AFC) test, subjects indicated which side of the tongue had a stronger irritant sensation. They also rated the intensity of irritation on each side separately. When NaCl was applied bilaterally, the side not previously receiving NaCl was chosen as stronger by a significant majority of subjects and was given significantly higher intensity ratings, consistent with self-desensitization. In contrast, when capsaicin was applied bilaterally, the side that had previously received sequential NaCl was perceived as having a significantly more intense irritation, consistent with cross-sensitization. In a second experiment, the effect of amiloride on NaCl-evoked irritation was studied. One side of the tongue was treated with 1 mM amiloride, after which 5 M NaCl was applied bilaterally and subjects performed the same 2-AFC and rating procedures. Since amiloride significantly reduced the intensity of the irritant sensation, the contribution of amiloride-sensitive ionic currents or the Na+/H+ exchange pump (NHE) are suggested as possible transduction mechanisms in lingual nociceptors mediating NaCl-evoked oral irritation.
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Affiliation(s)
- J M Dessirier
- Section of Neurobiology, Physiology, and Behavior, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
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