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Nolden AA, Lenart G, Spielman AI, Hayes JE. Inducible desensitization to capsaicin with repeated low-dose exposure in human volunteers. Physiol Behav 2024; 275:114447. [PMID: 38135109 PMCID: PMC10842799 DOI: 10.1016/j.physbeh.2023.114447] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/04/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023]
Abstract
Responses to capsaicin are reduced following repeated exposure, a phenomenon known as capsaicin desensitization. Heavy consumers of chilies consistently report reduced oral burn relative to infrequent consumers, presumably due to chronic desensitization. However, the mechanism(s) underlying capsaicin desensitization remain poorly understood. We hypothesized that reduced response to capsaicin due to repeated oral exposure may result from a change in the expression of the capsaicin receptor (TRPV1) gene. To test this, we conducted two longitudinal desensitization studies in healthy human volunteers. In Study 1, 51 adults completed a 17-day capsaicin desensitization protocol. The study consisted of three in-person visits where they were asked to sample stimuli, including 3, 6, and 9 ppm capsaicin, and rate intensity on a general labeled magnitude scale (gLMS). Between days 3 & 17, participants rinsed at home with 6 ppm capsaicin (n = 31) or a control (n = 20) solution (20 uM sucrose octaccetate; SOA) twice a day. Before and after the oral exposure protocol, a clinician collected fungiform papillae. Participants randomized to the capsaicin rinse showed a statistically significant reduction in oral burn ratings that was not observed in controls, indicating repeated low-dose exposure can systematically induce desensitization. TRPV1 expression was not associated with reported capsaicin burn, and there was no evidence of a decrease in TRPV1 expression following capsaicin exposure. In Study 2, participants (n = 45) rinsed with 6 ppm capsaicin in a similar protocol, rating capsaicin, vanillyl butyl ether (VBE), cinnamaldehyde, ethanol, menthol, and sucrose on days 1, 3, & 17. Burn from capsaicin, VBE, cinnamaldehyde, and ethanol all showed a statistically significant change - capsaicin, VBE and cinnamaldehyde burn all dropped ∼20 %, and a larger reduction was seen for ethanol - while menthol cooling and sucrose sweetness did not change. Collectively, this suggests reductions in oral burn following chronic capsaicin exposure generalizes to other stimuli (i.e., cross desensitization) and this cannot be explained by a change in TRPV1 mRNA expression. More work is needed to elucidate the underlying mechanism for capsaicin desensitization in the oral cavity.
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Affiliation(s)
- Alissa A Nolden
- Department of Food Science, University of Massachusetts, Amherst, MA, USA,; Sensory Evaluation Center, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Gabrielle Lenart
- Sensory Evaluation Center, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew I Spielman
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, NY, USA
| | - John E Hayes
- Sensory Evaluation Center, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
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Sawicki CM, Janal MN, Nicholson SJ, Wu AK, Schmidt BL, Albertson DG. Oral cancer patients experience mechanical and chemical sensitivity at the site of the cancer. BMC Cancer 2022; 22:1165. [PMID: 36368973 PMCID: PMC9650819 DOI: 10.1186/s12885-022-10282-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/04/2022] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Oral cancer patients suffer severe chronic and mechanically-induced pain at the site of the cancer. Our clinical experience is that oral cancer patients report new sensitivity to spicy foods. We hypothesized that in cancer patients, mechanical and chemical sensitivity would be greater when measured at the cancer site compared to a contralateral matched normal site. METHODS We determined mechanical pain thresholds (MPT) on the right and left sides of the tongue of 11 healthy subjects, and at the cancer and contralateral matched normal site in 11 oral cancer patients in response to von Frey filaments in the range of 0.008 to 300 g (normally not reported as painful). We evaluated chemical sensitivity in 13 healthy subjects and seven cancer patients, who rated spiciness/pain on a visual analog scale in response to exposure to six paper strips impregnated with capsaicin (0-10 mM). RESULTS Mechanical detection thresholds (MDT) were recorded for healthy subjects, but not MPTs. By contrast, MPTs were measured at the site of the cancer in oral cancer patients (7/11 patients). No MPTs were measured at the cancer patients' contralateral matched normal sites. Measured MPTs were correlated with patients' responses to the University of California Oral Cancer Pain Questionnaire. Capsaicin sensitivity at the site of the cancer was evident in cancer patients by a leftward shift of the cancer site capsaicin dose-response curve compared to that of the patient's contralateral matched normal site. We detected no difference in capsaicin sensitivity on the right and left sides of tongues of healthy subjects. CONCLUSIONS Mechanical and chemical sensitivity testing was well tolerated by the majority of oral cancer patients. Sensitivity is greater at the site of the cancer than at a contralateral matched normal site.
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Affiliation(s)
- Caroline M. Sawicki
- grid.137628.90000 0004 1936 8753Department of Pediatric Dentistry, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA
| | - Malvin N. Janal
- grid.137628.90000 0004 1936 8753Department of Epidemiology & Health Promotion, New York University College of Dentistry, Room 301, 433 First Avenue, New York, NY 10010 USA
| | - Samuel J. Nicholson
- grid.137628.90000 0004 1936 8753Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA
| | - Angie K. Wu
- grid.137628.90000 0004 1936 8753Bluestone Center for Clinical Research, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA
| | - Brian L. Schmidt
- grid.137628.90000 0004 1936 8753Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA ,grid.137628.90000 0004 1936 8753Bluestone Center for Clinical Research, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA ,grid.137628.90000 0004 1936 8753NYU Oral Cancer Center, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA
| | - Donna G. Albertson
- grid.137628.90000 0004 1936 8753Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA ,grid.137628.90000 0004 1936 8753Bluestone Center for Clinical Research, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA ,grid.137628.90000 0004 1936 8753NYU Oral Cancer Center, New York University College of Dentistry, 421 First Avenue, Room 233W, New York, NY 10010 USA
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Lee JJ, Lee S, Lee DH, Woo CW. Functional brain reconfiguration during sustained pain. eLife 2022; 11:74463. [PMID: 36173388 PMCID: PMC9522250 DOI: 10.7554/elife.74463] [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: 10/05/2021] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Pain is constructed through complex interactions among multiple brain systems, but it remains unclear how functional brain networks are reconfigured over time while experiencing pain. Here, we investigated the time-varying changes in the functional brain networks during 20 min capsaicin-induced sustained orofacial pain. In the early stage, the orofacial areas of the primary somatomotor cortex were separated from other areas of the somatosensory cortex and integrated with subcortical and frontoparietal regions, constituting an extended brain network of sustained pain. As pain decreased over time, the subcortical and frontoparietal regions were separated from this brain network and connected to multiple cerebellar regions. Machine-learning models based on these network features showed significant predictions of changes in pain experience across two independent datasets (n = 48 and 74). This study provides new insights into how multiple brain systems dynamically interact to construct and modulate pain experience, advancing our mechanistic understanding of sustained pain.
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Affiliation(s)
- Jae-Joong Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sungwoo Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.,Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
| | - Dong Hee Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.,Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
| | - Choong-Wan Woo
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.,Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
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Roukka S, Puputti S, Aisala H, Hoppu U, Seppä L, Sandell MA. The Individual Differences in the Perception of Oral Chemesthesis Are Linked to Taste Sensitivity. Foods 2021; 10:foods10112730. [PMID: 34829011 PMCID: PMC8618882 DOI: 10.3390/foods10112730] [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: 09/28/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Chemesthesis is a part of the flavor experience of foods. Chemesthetic perception is studied to understand its effect on food-related behavior and health. Thus, the objective of this research was to study individual differences in chemesthetic perception. Our study involved sensory tests of three chemesthetic modalities (astringency, pungency, and cooling). Participants (N = 196) evaluated the intensity of samples in different concentrations using a line scale under sensory laboratory conditions. Aluminum ammonium sulfate, capsaicin, and menthol were used as the prototypic chemesthetic compounds. The participants were divided into sensitivity groups in different chemesthetic modalities by hierarchical clustering based on their intensity ratings. In addition, an oral chemesthesis sensitivity score was determined to represent the generalized chemesthesis sensitivity. The results showed that people can perceive chemesthesis on different intensity levels. There were significantly positive correlations between (1) sensitivity scores for oral chemesthesis and taste as well as (2) each chemesthesis and taste modalities. Moreover, based on the multinomial logistic regression model, significant interactions between oral chemesthesis and taste sensitivity were discovered. Our findings showed that people can be classified into different oral chemesthesis sensitivity groups. The methods and results of this study can be utilized to investigate associations with food-related behavior and health.
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Affiliation(s)
- Sulo Roukka
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland; (S.R.); (L.S.)
| | - Sari Puputti
- Functional Foods Forum, University of Turku, 20014 Turku, Finland; (S.P.); (H.A.); (U.H.)
| | - Heikki Aisala
- Functional Foods Forum, University of Turku, 20014 Turku, Finland; (S.P.); (H.A.); (U.H.)
| | - Ulla Hoppu
- Functional Foods Forum, University of Turku, 20014 Turku, Finland; (S.P.); (H.A.); (U.H.)
| | - Laila Seppä
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland; (S.R.); (L.S.)
| | - Mari A. Sandell
- Department of Food and Nutrition, University of Helsinki, 00014 Helsinki, Finland; (S.R.); (L.S.)
- Functional Foods Forum, University of Turku, 20014 Turku, Finland; (S.P.); (H.A.); (U.H.)
- Correspondence: ; Tel.: +358-29-415-8234
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Liu DT, Besser G, Bayer K, Prem B, Mueller CA, Renner B. Bitter Taste Disrupts Spatial Discrimination of Piperine-Evoked Burning Sensations: A Pilot Study. BIOLOGY 2021; 10:biology10090886. [PMID: 34571763 PMCID: PMC8469466 DOI: 10.3390/biology10090886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022]
Abstract
Simple Summary The chemical senses smell, taste, and trigeminal sense enable us to interact with the environment and play an essential role in protecting us from hazardous events. It is theorized that capsaicin and piperine not only elicit burning, but also bitter sensations through bitter taste-responding gustatory receptor cells that possess special channels. Similar psychophysiological responses to capsaicin and piperine suggest that bitter taste might also disrupt the spatial discrimination to piperine-induced burning sensations. Results showed that bitter taste disrupted the spatial discrimination of piperine-evoked burning sensations, providing further evidence for a qualitative similarity between burning and bitter sensations and the usefulness of chemical irritants in spatial discrimination tasks. Abstract This study aimed to investigate the perceptual similarity between piperine-induced burning sensations and bitter taste using piperine-impregnated taste strips (PTS). This pilot study included 42 healthy participants. PTS of six ascending concentrations (1 mg, 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg piperine/dL 96% ethanol) were presented at the anterior tongue, and participants rated perceived intensity and duration. Then, participants performed a spatial discrimination task in which they had to report which of the two strips presented to the anterior tongue contained an irritating stimulus when one strip was always a PTS while the other strip was impregnated with either a single taste quality (sweet or bitter) or a blank strip. Repeated measures one-way ANOVA revealed that burning sensations of higher concentrated PTS were perceived more intense and more prolonged compared to lower concentrated PTS. McNemar’s test showed that PTS were identified correctly significantly less often when presented with bitter strips compared to when presented with blank (p = 0.002) or sweet strips (p = 0.017). Our results showed that bitter taste disrupts the spatial discrimination of piperine-evoked burning sensations. PTS might serve as a basis for further studies on disease-specific patterns in chemosensory disorders.
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Affiliation(s)
- David T. Liu
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria; (D.T.L.); (G.B.); (K.B.); (B.P.)
| | - Gerold Besser
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria; (D.T.L.); (G.B.); (K.B.); (B.P.)
| | - Karina Bayer
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria; (D.T.L.); (G.B.); (K.B.); (B.P.)
| | - Bernhard Prem
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria; (D.T.L.); (G.B.); (K.B.); (B.P.)
| | - Christian A. Mueller
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria; (D.T.L.); (G.B.); (K.B.); (B.P.)
- Correspondence:
| | - Bertold Renner
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany;
- Institute of Clinical Pharmacology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
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Abstract
Taste disorders, impacting well-being and physical health, can be caused by many etiologies including the use of medication. Recently, taste disturbance is also considered as one of the predominant symptoms of COVID-19 although its pathogenesis requires further research. Localized taste disorders may be overlooked considering that whole-mouth taste perception is insured through several mechanisms. Individuals often fail to discern taste from flavor, and interviews/surveys are insufficient to properly assess taste function. Hence, various taste assessment methods have been developed. Among them, psychophysical methods are most widely applied in a clinical context. Less-biased electrophysiological, imaging, or morphological methods are used to a much lesser degree. Overall, more research is needed in the field of taste.
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Affiliation(s)
- Y Zhu
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden University Hospital, Dresden, Germany
| | - T Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden University Hospital, Dresden, Germany.
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Berry DN, Simons CT. Do Caucasian American and South Asian Indian cultural groups differ in sensitivity to capsaicin? A study designed to control for chili pepper affinity. J Food Sci 2020; 85:2896-2901. [PMID: 32794204 DOI: 10.1111/1750-3841.15369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/24/2020] [Accepted: 06/30/2020] [Indexed: 11/29/2022]
Abstract
Although different cultural groups are known to vary in their tolerance for hot chili peppers, the influence of factors such as cultural background and upbringing on sensitivity to compounds in spicy food is unclear. A study was designed to investigate sensitivity differences to capsaicin between Caucasian American and South Asian Indian cultural groups while controlling for general chili pepper affinity. The two cultural groups were selected to match on metrics related to chili pepper use and liking. Subjects were exposed to a capsaicin (100 ppm) stimulus on the tongue, cheek, hard palate, and lip and rated the intensity of irritation every 30 s, over a 10-min period. Overall sensitivity to capsaicin in the oral cavity did not differ between the groups, nor were responses different between the groups depending on the oral cavity area stimulated. These data suggest a limited role of cultural attributes on capsaicin sensitivity between Caucasian Americans and South Asian Indians. The methods and findings here provide subject recruitment insight and guidance on effectively designing a sensory study to answer perceptual questions regarding specific subject groups. PRACTICAL APPLICATION: This study design provides a model for researchers interested in utilizing sensory testing to answer questions about subject groups. Although the objective of this study regarded sensitivity differences across two cultural groups, alterations in the subject matching process used presently could be easily implemented to investigate sensitivity across other differing subject characteristics of interest.
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Affiliation(s)
- Danica N Berry
- Department of Food Science & Technology, The Ohio State University, 2015 Fyffe Rd, Columbus, OH, 43210, U.S.A
| | - Christopher T Simons
- Department of Food Science & Technology, The Ohio State University, 2015 Fyffe Rd, Columbus, OH, 43210, U.S.A
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